#include <bits/stdc++.h>
using namespace std;
long long mod = 1000000007;
long long INF = 1000000009;
void solve() {
  int n, h;
  cin >> n >> h;
  int a[n + 10];
  int b[n + 10];
  for (long long i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
  }
  sort(a, a + n, greater<int>());
  sort(b, b + n, greater<int>());
  int ans = 0;
  int pointer = 0;
  while (h > 0) {
    if (b[pointer] > a[0]) {
      h = h - b[pointer];
      pointer++;
      ans++;
    } else {
      if (h % a[0] == 0) {
        ans += h / a[0];
        h = 0;
      } else {
        ans += h / a[0] + 1;
        h = 0;
      }
    }
  }
  cout << ans << endl;
}
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  solve();
  return 0;
}
