#include <bits/stdc++.h>
using namespace std;
const long long mod = 1000000007;
const long long INF = 100000000000;
string u = "abcdefghijklmnopqrstuvwxyz";
int main() {
  int N;
  cin >> N;
  long long H;
  cin >> H;
  long long a[N], b[N];
  for (int i = 0; i < N; i++) {
    cin >> a[i] >> b[i];
  }
  long long am = 0;
  long long ans = 0;
  sort(a, a + N);
  am = a[N - 1];
  for (int i = 0; i < N; i++) {
    if (am <= b[i]) {
      H -= b[i];
      ans++;
    }
    if (H <= 0) {
      cout << ans << endl;
      return 0;
    }
  }
  while (0 < H) {
    H -= am;
    ans++;
  }
  cout << ans << endl;
  return 0;
}
