n, k = input().split(" ")
n = int(n)
k = int(k)
def works(value):
total_candies_provisioned = (value * (value + 1)) // 2
return total_candies_provisioned - (n - value) - k
def binary_search():
if n == 1:
return 0
L = 0
R = 10 ** 9
while L <= R:
mid = (L + R) // 2
result = works(mid)
if result == 0:
return n - mid
elif result < 0:
L = mid + 1
else:
R = mid - 1
print(binary_search())#include<bits/stdc++.h>
#define ll long long int
#define whole(v) v.begin(),v.end()
#define rwhole(v) v.rbegin(),v.rend()
#define endl '\n'
#define pb push_back
#define Speedforce ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
using namespace std;
ll egcd(ll a, ll b)
{
if(a%b == 0) return b;
else return egcd(b, a%b);
}
int main()
{
Speedforce;
ll t, n, d, i, j, k, x, y, tmp, tmp1;
cin >> x >> y;
ll high = x, low = 1, mid = (high+low)/2;
d = (mid*(mid+1)/2);
ll ate = x-mid;
ll left = d-ate;
while(1)
{
if(left == y) break;
else if(left > y)
{
high = mid;
mid = (high+low)/2;
d = (mid*(mid+1)/2);
ate = x - mid;
left = d-ate;
}
else
{
low = mid;
mid = (high+low)/2;
d = (mid*(mid+1)/2);
ate = x - mid;
left = d-ate;
}
}
cout << ate << endl;
}1030B - Vasya and Cornfield | 1631A - Min Max Swap |
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1650D - Twist the Permutation | 1209A - Paint the Numbers |
1234A - Equalize Prices Again | 1613A - Long Comparison |
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405A - Gravity Flip | 499B - Lecture |
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217A - Ice Skating | 270A - Fancy Fence |
181A - Series of Crimes | 1638A - Reverse |
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1649A - Game | 139A - Petr and Book |