#include <bits/stdc++.h>
using namespace std;
long long mod = pow(10, 9) + 7;
int main() {
  int N, H, i, a, b, a_max = 0, ans = 0;
  cin >> N >> H;
  vector<int> B(100000);
  for (i = 0; i < (N); ++i) {
    cin >> a >> b;
    a_max = max(a_max, a);
    B[i] = b;
  }
  sort(B.begin(), B.begin() + N);
  i = N - 1;
  int sum = 0;
  while (i >= 0) {
    if (B[i] > a_max) {
      sum += B[i];
      ans++;
    } else
      break;
    i--;
  }
  cout << ans + (H - sum + a_max - 1) / a_max << endl;
  return 0;
}
