#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int n, h, i, maxi = 0, c = 0, sum = 0;
  cin >> n >> h;
  vector<long long int> v;
  for (i = 1; i <= n; i++) {
    long long int x, y;
    cin >> x >> y;
    sum = sum + y;
    if (sum >= h && c == 0) c = i;
    if (x > maxi) maxi = x;
    v.push_back(y);
  }
  if (sum >= h)
    cout << n << endl;
  else {
    h = h - sum;
    c = n;
    if (h % c == 0)
      cout << c + (h / maxi) << endl;
    else
      cout << c + 1 + (h / maxi) << endl;
  }
  return 0;
}
