121A - Lucky Sum - CodeForces Solution

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define loop(a, b, c) for (int(a) = (b); a < (c); a++)
#define nl '\n'
#define MAXN   10000
#define fast ios_base::sync_with_stdio(0); cin.tie(0);
const ll int N = 1e9;
/*⠀⠀⠀⠀⠀⠀⠀⠀

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣀⣀⣀⣀⣠⣴⣶⣶⣶⣶⣿⣿⣶⣶⣶⣤⣀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣠⣤⣶⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣶⣤⣄⣀⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⣤⣾⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⠿⣿⣿⣿⣿⣿⣦⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢠⣿⣿⣿⣿⠟⠙⣿⣿⠈⣿⣿⣿⠟⠟⣿⣿⣿⣿⣿⣯⣇⣿⣿⣿⡏⣀⣩⡿⢿⣿⣿⣿⣿⣦⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⣾⣿⠋⣫⢁⣄⣿⣹⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣶⣄⣘⣿⣿⣿⣿⣷⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢸⣿⣿⣶⣿⣿⣿⡿⠿⠿⢿⣿⣿⢿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⡄⠘⢿⣿⣿⣿⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣼⣿⣿⣿⣿⠋⠉⠀⠀⠀⠀⠀⠀⠈⠉⠉⠛⠛⠛⠛⠙⠻⠛⠉⠉⠉⠉⠙⠛⢿⣿⣿⣇⣀⣠⣿⣿⣿⣿⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢰⣿⣿⣿⣿⠃⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀   ⠀⠉⢿⣿⣿⣿⣿⣿⣿⣿⡆⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢸⣿⣿⣿⠇⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀   ⠀⠀⠀⠀⢸⣯⠉⢿⣿⣿⣿⣿⣷⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⣿⣿⣿⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀   ⠀⠀⠈⢿⣦⡀⠹⢿⣿⣿⣿⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢸⣿⣿⡟⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣀⣀⠀⠀⠀⠀⠀⠀⠀    ⠀⠈⢻⡄⢨⣿⣿⣿⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢸⣿⣿⢃⣠⣶⣿⣿⣶⣤⣤⣄⣀⠀⠀⠀⠀⠀⣀⣤⣴⣿⣿⣿⣿⣿⣿⣿⣧⠀⠀⠀⠀⠀⠀⢤⣽⣓⠻⣿⣿⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣿⡇⣿⡿⠁⢀⣀⣈⣉⣻⣿⡿⠁⠀⠀⠀⢸⣿⣿⠟⡩⠿⣶⣤⣉⡙⠿⣿⡄⠀⠀⠀⠀⠀⢸⣿⣿⡃⣿⠃⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢹⡇⠉⠀⣴⣶⣿⣿⠻⣿⣿⣿⡆⠀⠀⠀⠘⣿⣿⣾⣷⣿⣿⣿⣿⣿⣶⣍⠁⠀⠀⠀⠀⠀⢸⣿⣿⣿⣿⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣸⡇⠀⠀⠏⠉⠉⠁⢠⣾⣿⠟⠀⠀⠀⠀⠀⠘⢿⣿⣿⣌⠭⢬⣧⡀⠉⠛⠃⠀⠀⠀⠀⠀⠈⣿⣿⣿⣿⣄⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣾⣿⠃⠀⠀⠀⠐⠒⢚⡭⠟⠁⠀⠀⠀⠀⠀⠀⠀⠀⠙⠛⠻⠿⠶⠾⣟⡉⠀⠀⠀⠀⠀⠀⠀⠀⠸⠟⣣⢷⣾⡇⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣿⣿⡀⠀⠀⠀⠀⠀⠉⠀⠀⢀⡆⠀⠀⠀⠀⠀⠀⠀⣼⣦⠀⠀⠀⠀⠀⠉⠀⠀⠀⠀⠀⠀⠀⠀⠀⣠⡉⠀⣿⠇⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢰⣿⣿⡇⠀⠀⠀⠀⠀⠀⠀⣴⡟⢀⠀⢀⣀⠀⠀⠀⠀⢻⣿⣷⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢸⣿⡆⢻⡆⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢸⣿⣿⡇⠀⠀⠀⠀⠀⢀⣼⠟⠶⠿⠆⣼⣿⡟⠰⠾⢷⡾⠿⣿⣿⣦⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣼⣿⡇⣾⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⣿⢿⡇⠀⠀⠀⠀⢀⡾⠉⠀⣀⣀⣀⣭⣿⢿⣿⠷⣶⣷⣦⣜⣿⠿⣷⡄⠀⠀⠀⠀⠀⠀⠀⠀⠀⠸⠟⠉⣼⠃⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣿⣿⡇⠀⠀⠀⠰⠇⣠⣶⣿⣿⣿⣿⣿⣿⣿⣿⣷⣿⣿⢿⣿⣿⣤⠙⠃⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣼⠁⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠘⢿⣇⠀⠀⠀⢀⣾⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣾⣟⣿⣿⣿⣷⣄⠀⠀⠀⠀⠀⠀⠀⠀⢸⣷⠞⠁⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢹⡀⢦⣤⣾⣿⣿⣿⣿⣿⠿⠛⠛⠛⠛⠿⢿⣿⣿⣿⣿⣿⣿⣿⣿⣷⣦⡶⠀⠀⠀⠀⠀⢸⡇⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠘⣇⠀⠙⠛⠻⣿⠟⠋⠀⠀⢀⣠⣾⣿⣿⣿⣿⠛⠛⠛⠛⠛⠛⠛⠉⠀⠀⠀⠀⠀⠀⠀⣿⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢻⣄⠀⠀⠀⠁⠀⠀⠀⠀⠘⠿⠿⠿⠿⠿⠿⠓⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣼⠃⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣿⣆⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⡏⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⣿⣿⡳⣄⢀⠀⠀⠀⠀⠀⠀⢀⣤⣤⣀⣀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢸⣄⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣠⣿⣿⣿⣿⣯⣻⢿⣷⣦⣤⣤⣶⣿⣿⣿⣿⣿⣿⣦⠀⢀⣀⣠⠴⠄⠀⠀⠀⠀⠀⣾⣿⣧⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣰⣿⣿⣿⣿⣿⣿⣿⡳⣯⡻⠛⠛⠿⠿⠿⣿⣿⣿⣿⣿⠿⠋⠉⠀⠀⠀⠀⠀⠀⠀⣰⣿⣿⣿⣧⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣠⣾⣿⣿⣿⣿⣿⣿⣿⣿⣿⣦⡹⣦⠀⠀⠀⠀⠈⣿⣿⣿⣇⠀⠀⠀⠀⠀⠀⠀⠀⢀⣴⣿⣿⣿⣿⣿⣿⣷⣤⣀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⣀⣀⣤⣴⡾⢻⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣮⡳⣤⡀⠀⠀⢻⣿⣿⣿⡆⠀⠀⠀⠀⠀⢀⣤⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣶⣤⣤⣀⡀⠀⠀⠀⠀
⠀⢀⣠⣴⣶⣿⣿⣿⡿⢟⣳⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⢿⣿⣿⣿⣿⣿⣦⣍⠲⢤⡀⠈⠙⢿⣇⠀⠀⠀⣀⡴⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣷⡾⣿⣿⣿⣿⣿⣷⣦⣀⠀
⢿⣿⣿⣿⡿⢟⣻⣥⣶⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⡟⣵⣌⠻⣿⣿⣿⣿⣿⣿⣿⣦⡙⠳⣤⣼⣧⣀⡤⢚⣵⣾⣿⣿⣿⣿⣿⢏⡛⠿⣿⣿⣿⣿⣿⣿⣷⣶⣿⣽⣿⣿⣿⣿⣿⠇
⠀⠙⠛⠻⣾⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⢏⣾⡿⢿⣷⡽⣿⣿⣿⣿⣿⣿⣿⣿⣷⢲⣤⣽⣥⣾⣿⣿⣿⣿⣿⣿⣿⡟⢸⡿⠳⣌⠛⢿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⡿⠋⠀
⠀⠀⠀⠀⠙⢿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⢿⡁⢀⣼⠀⣿⡟⢿⣿⣿⣿⣿⣿⣿⣿⡀⠈⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⡇⣿⡀⢀⡙⢻⡄⣿⣿⣿⣿⣿⣿⣿⣿⠿⠋⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠈⠉⠛⠻⠿⢿⣿⣿⣿⣿⣿⣿⣮⢳⣾⣧⣾⣿⣿⣎⢿⣿⣿⣿⣿⣿⡿⠁⣼⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⠁⣿⣿⣾⣷⣿⠇⣿⣿⣿⣿⡿⠛⠉⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⠛⢿⣿⣿⣿⣷⣿⣿⣿⣿⣿⣿⣦⡻⣿⣿⣿⠟⢀⣼⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⡇⢸⣿⣿⣿⣿⣿⠀⣿⣿⡟⠃⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠉⠻⢿⣿⣿⣿⣿⣿⣿⣿⣿⣽⠟⠁⢀⣾⣿⣿⡄⢠⣿⣿⣿⣿⣿⣿⣿⠃⣼⣿⣿⣿⣿⡇⠀⣿⠋⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
 */
/*
vector<ll> getFactorization(ll x)
{
    vector<ll> ret;
    while (x != 1)
    {
        ret.push_back(spf[x]);
        x = x / spf[x];
    }
    return ret;
}
int computeXOR(int n)
{

    // If n is a multiple of 4
    if (n % 4 == 0)
        return n;

    // If n%4 gives remainder 1
    if (n % 4 == 1)
        return 1;

    // If n%4 gives remainder 2
    if (n % 4 == 2)
        return n + 1;

    // If n%4 gives remainder 3
    return 0;
}

ll length(ll z)
{
    ll a=0;
    while(z)
    {
        a++;
        z/=10;
    }
    return a;
}


int prime(int z)
{
    for (int i = 2; i*i<=z;i++)
    {
        if(z%i==0)
        {
            return 1;
        }
    }
    return 0;
}


ll fastpow(ll a,ll b,ll mod)
{
    if(b==0)
    {
        return 1;
    }
    ll res= fastpow(a,b/2,mod);
    res=(res*res)%mod;
    if(b%2==1)
    {
        res=(res*a)%mod;
    }
    return res;
}



int setBitNumber(int n)
{
    if (n == 0)
        return 0;

    int msb = 0;
    n = n / 2;
    while (n != 0) {
        n = n / 2;
        msb++;
    }

    return (1 << msb);
}
        if (spf[i] == i)
        {

            for (int j=i*i; j<N; j+=i)


                if (spf[j]==j)
                    spf[j] = i;
        }
    }
}
long long nextpowerof2(ll p)
{
    if(!(p&(p-1)))
    {
        return p;
    }
    return 0x8000000000000000>>(__builtin_clzll(p)-1);
}
*/

bool prime[10000001];

void Sieve(){
    memset(prime, true, sizeof(prime));

    for (int p=2;p*p<=10000000;p++){
        if (prime[p]){
            for (int i=p*p;i<=10000000;i+=p){
                prime[i]=false;
            }
        }
    }
}

bool sortbysec(const pair<ll,ll> &a,
               const pair<ll,ll> &b)
{
    return (a.second < b.second);
}

bool cmp(pair<int,int>&a, pair<int, int>&b)
{
    if(a.first>b.first)
    {
        return true;
    }
    if(a.first==b.first && a.second< b.second)
    {
        return true;
    }
    return false;
}
vector<ll>lucky;

void check(ll l)
{
    if(l>1e10)
    {
        return ;
    }
    lucky.push_back(l);
    check((l*10)+4);
    check((l*10)+7);
}

int main() {
    check(0);
    lucky.erase(lucky.begin());
    fast;
    ll x,y;
    cin>>x>>y;

    sort(lucky.begin(),lucky.end());
    ll o= lower_bound(lucky.begin(),lucky.end(),x)-lucky.begin();
    ll ans=0;
    for(ll i=x;i<=y;i++)
    {
         while(i>lucky[o])
         {
             o++;
         }
         ans+=lucky[o];
    }
    cout<<ans<<endl;
}