Shared code

/* 777 */
#include <bits/stdc++.h>
using namespace std;
#define FAST_IO ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

void solve() {
    int n; cin >> n;
    vector<pair<int,int>> vec;
    while (n--) {
        int t, d; cin >> t >> d;
        vec.emplace_back(t, d);
    }
    sort(vec.begin(), vec.end());
    long long res = 0, cur = 0;
    for (auto& [t, d] : vec) {
        cur += t;
        res += d - cur;
    }
    cout << res;
}

int32_t main() {
    FAST_IO
    solve();
}