#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, h;
  cin >> n >> h;
  vector<long long> b(n);
  long long a_max = 0;
  long long temp;
  for (int i = 0; i < (n); ++i) {
    cin >> temp;
    a_max = max(a_max, temp);
    cin >> temp;
    b[i] -= temp;
  }
  sort((b).begin(), (b).end());
  long long ans = ceil(double(1.0 * h / a_max));
  for (int i = 0; i < (n); ++i) {
    if (a_max < -1 * b[i]) {
      h += b[i];
      ans = min(ans, long long(i + 1 + ceil(double(1.0 * h / a_max))));
    } else {
      break;
    }
  }
  cout << ans << endl;
  return 0;
}
