#include <bits/stdc++.h>
using namespace std;
int n, h, mx, c, a, b[100005];
int main() {
  int i;
  cin >> n >> h;
  for (i = 0; i < n; i++) scanf("%d %d", &a, &b[i]), mx = max(mx, a);
  for (i = 0; i < n; i++)
    if (b[i] > mx && h > 0) h -= b[i], c++;
  cout << c + (h > 0) * ((h - 1) / mx + 1) << endl;
  return 0;
}
