#include <bits/stdc++.h>
using namespace std;
const int lim = 1000000007;
int main() {
  int N, H;
  cin >> N >> H;
  vector<int> a(N), b(N);
  for (int i = 0; i < N; i++) cin >> a[i] >> b[i];
  int mx_a = 0;
  for (int i = 0; i < N; i++) mx_a = max(mx_a, a[i]);
  int cnt = 0;
  long long sum = 0;
  for (int i = 0; i < N; i++) {
    if (b[i] > mx_a) {
      cnt++;
      sum += b[i];
    }
    if (sum >= H) {
      cout << cnt << endl;
      return 0;
    }
  }
  int d = H - sum;
  int c = (d + mx_a - 1) / mx_a;
  int ans = c + cnt;
  cout << ans << endl;
  return 0;
}
