#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, h;
  int a[100001] = {};
  int b[100001] = {};
  cin >> n >> h;
  int m = 0;
  for (int i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
    if (a[i] > m) {
      m = a[i];
    }
  }
  long long int ans = 0;
  sort(b, b + n);
  for (int i = n - 1; i >= 0; i--) {
    if (m < b[i]) {
      h -= b[i];
      ans++;
    } else {
      break;
    }
  }
  if (h > 0) {
    if (h % m == 0) {
      ans += h / m;
    } else {
      ans += h / m + 1;
    }
  }
  cout << ans << endl;
  return 0;
}
