#include <iostream>
#include <algorithm>
using namespace std;

struct Milk
{
    long long p, c;
}m[100010];

bool cmp(Milk x, Milk y)
{
    return x.p < y.p;
}

int main()
{
    long long n, b;
    cin >> n >> b;
    for (int i = 1; i <= n; i++)
    {
        cin >> m[i].p >> m[i].c;
    }
    sort(m + 1, m + n + 1, cmp);
    long long cnt = 0;
    for (int i = 1; i <= n; i++)
    {
        if (b >= m[i].p * m[i].c)
        {
            b -= m[i].c * m[i].p;
            cnt += m[i].c;
        }
        else
        {
            cnt += b / m[i].p;
            break;
        }
    }
    cout << cnt << endl;
    return 0;
}

救您