#include <iostream>
#include <vector>
using namespace std;
int main(){
    int n, m;
    cin >> n >> m;
    vector<int> num(n);
    for(int i = 0; i < n; i++){
        int a, b;
        cin >> a >> b;
        num[i] = a * b;
    }
    int sum = 0;
    int cnt = 0;
    for(int i = 0; i < n; i++){
        
        sum += num[i];
        cnt += 2;
        if(sum >= m) break;
    }
    cout << cnt << endl;
    return 0;
}