#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, h, max_a, i, attack;
  cin >> n >> h;
  int a[n], b[n];
  for (i = 0; i < n; i++) cin >> a[i] >> b[i];
  max_a = 0;
  for (i = 1; i < n; i++)
    if (a[i] > a[max_a]) max_a = i;
  for (i = 0; i < n; i++) {
    if (max_a == i) continue;
    h -= b[i];
  }
  attack = n - 1;
  if (h > b[max_a]) {
    h -= b[max_a];
    attack++;
    attack += h / a[max_a];
  } else
    attack++;
  cout << attack << endl;
  return 0;
}
