#include <bits/stdc++.h>
using namespace std;
const int max_N = 100006;
long long int a[max_N], b[max_N];
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  ;
  long long int n, h, amax;
  while (cin >> n >> h) {
    amax = 0;
    for (int i = 0; i < n; i++) {
      cin >> a[i] >> b[i];
      amax = max(amax, a[i]);
    }
    long long int round = 0;
    sort(b, b + n);
    for (int i = n - 1; i >= 0; i--) {
      if (h <= 0) {
        break;
      } else {
        h -= b[i];
        round++;
      }
    }
    while (h > 0) {
      h -= amax;
      round++;
    }
    cout << round << endl;
  }
  return 0;
}
