189C - Permutations - CodeForces Solution

#include <bits/stdc++.h>
#include <algorithm>

using namespace std;

namespace IO{
    void setIn(string s) {freopen(s.c_str(), "r", stdin);}
    void setOut(string s) {freopen(s.c_str(), "w", stdout);}
    void setIO(string s = ""){
        ios_base::sync_with_stdio(false);
        cin.tie(0); cout.tie(0);
        #ifndef ONLINE_JUDGE
        #endif // ONLINE_JUDGE
        if (s.size()){
            setIn(s+".inp");
            setOut(s+".out");
        } else{
            #ifndef ONLINE_JUDGE
                freopen("input.txt", "r", stdin);
            #endif // ONLINE_JUDGE
        }
    }
}

using namespace IO;

namespace Function{
    template <typename T1, typename T2> bool amax(T1 &a, T2 b){
        if (a < b) {
            a = b;
            return 1;
        }
        return 0;
    }
    template <typename T1, typename T2> bool amin(T1 &a, T2 b){
        if (a > b){
            a = b;
            return 1;
        }
        return 0;
    }
    template <typename T> void compress(T &a){
        sort(a.begin(), a.end());
        a.resize(unique(a.begin(), a.end()) - a.begin());
    }
    template <typename T1, typename T2, typename T3> int position(T1 Begin, T2 End, T3 val, bool type = 0){
        if (type == 0){
            return lower_bound(Begin, End, val) - Begin;
        }
        return upper_bound(Begin, End, val) - Begin;
    }

    template <typename T> long long sqr(T x) {return 1LL * x * x;}

    template <typename T1, typename T2> long long pow_mod(T1 a, T2 b, long long mod = 1){ //a ^ b % mod
        if(b == 0){return 1 % mod;}
        else{
            if(b % 2 == 0){
                return sqr(pow_mod(a, b / 2, mod)) % mod;
            }else{
                return a * (sqr(pow_mod(a, b / 2, mod)) % mod) % mod;
            }
        }
    }
  
    template <typename T1, typename T2> long long GCD(T1 a, T2 b) {return b == 0 ? a : GCD(b, a % b);}
    template <typename T1, typename T2> long long LCM(T1 a, T2 b) {return 1LL * a / GCD(a, b) * b;}
}

using namespace Function;

namespace Output{
    char End_Of_Stream = '\n';
    void print(int x) {cout << x << End_Of_Stream;}
    void print(unsigned int x) {cout << x << End_Of_Stream;}
    void print(long unsigned int x) {cout << x << End_Of_Stream;}
    void print(long long x) {cout << x << End_Of_Stream;}
    void print(unsigned long long x) {cout << x << End_Of_Stream;}
    void print(float x) {cout << x << End_Of_Stream;}
    void print(double x) {cout << x << End_Of_Stream;}
    void print(long double x) {cout << x << End_Of_Stream;}
    void print(char x) {cout << x << End_Of_Stream;}
    void print(const char* x) {cout << x << End_Of_Stream;}
    void print(string x) {cout << x << End_Of_Stream;}
    void print(bool x) {cout << x << End_Of_Stream;}

    template <typename T1, typename T2> void print(pair <T1, T2> a) {cout << a.first << " " << a.second << End_Of_Stream;}
    template <size_t sz> void print(bitset<sz> a) {
        for(int i = 0; i < sz; i++){
            cout << a[i];
        }
        cout << End_Of_Stream;
    }

    template <typename T> void write(T x) {print(x);}

    template <class T, class... Ts> void write(T t, Ts... ts){
        write(t);
        write(ts...);
    }

    template <class T, class... Ts> void print(T t, Ts... ts){
        End_Of_Stream = ' ';
        write(t, ts...);
        cout << '\n';
        End_Of_Stream = '\n';
    }

    template <typename T> void print(T a){
        for(auto it : a){
            cout << it << " ";
        }
        cout << "\n";
    }

    template <typename T> void prints(T a){
        for(auto it : a){
            print(it);
        }
    }

    template <class T, class... Ts> void prine(T t, Ts... ts){
        print(t, ts...);
        exit(0);
    }
}

using namespace Output;

typedef pair <int, int> pii;
typedef long long ll;
#define fi first
#define se second


const int dx[] = {1, -1, 0, 0};
const int dy[] = {0, 0, 1, -1};
const int dx1[] = {1, -1, 0, 0, -1, 1, -1, 1};
const int dy1[] = {0, 0, 1, -1, -1, -1, 1, 1};
const int INF = 1e9 + 10;
const long long INFL = 1e18 + 1e15;
const long long MOD = 1e9 + 7;
const long long MOD1 = (119 << 23) + 1;
const int N = 2e5 + 5;



int main(){
    // setIO();
    ios_base::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);

    int n;
    cin >> n;
    vector<int> vec1(n), vec2(n);
    for(int i = 0; i < n; i++){
        cin >> vec1[i];
    }
    for(int i = 0; i < n; i++){
        cin >> vec2[i];
    }
    int cnt = 0;
    int id = 0;
    for(int i = 0; i < n; i++){
        if(vec1[id] == vec2[i]){
            id++;
            cnt++;
        }
    }
    print(n - cnt);


    return 0;
}