#include <bits/stdc++.h>
using namespace std;
signed main() {
  long long b = 0, f = 0, g = 0, c, d;
  long long a;
  cin >> a >> d;
  for (long long i = 0; i < a; i++) {
    cin >> c >> b;
    d -= b;
    g = max(g, c);
  }
  if (d % g != 0) f = 1;
  cout << d / g + f + a << "\n";
}
