cbuying.cpp

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;

int main() {
    int n; ll b;
    cin >> n >> b;
    vector<pair<ll,ll>> a(n);
    for (auto &i : a) {
        cin >> i.first >> i.second;
    }
    sort(a.begin(), a.end());
    ll ans = 0;
    for (auto &i : a) {
        ll t = min(b / i.first, i.second);
        b -= t * i.first;
        ans += t;
    }
    cout << ans << '\n';
}