#include <bits/stdc++.h>
const int mod = 1e9 + 7;
const int inf = 1 << 20;
const long long INF = 1LL << 60;
using namespace std;
using namespace std;
int main() {
  int n, h;
  cin >> n >> h;
  int a[n], b[n];
  int x = 0;
  int ans = 0;
  for (int i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
    x = max(x, a[i]);
  }
  for (int i = 0; i < n; i++) {
    if (h <= 0) {
      break;
    } else if (x <= b[i]) {
      h -= b[i];
      ans++;
    }
  }
  if (h > 0) {
    ans += ((h - 1) / x);
    ans++;
  }
  cout << ans << endl;
}
