10833. 사과

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

using namespace std;

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

    int N;
    cin >> N;

    int ans = 0;
    for(int i = 0; i < N; i++){
        int stu, app;
        cin >> stu >> app;

        ans += app % stu;
    }

    cout << ans << "\n";

    return 0;
}
``