#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  long long int h;
  cin >> n >> h;
  vector<int> b(n);
  int a, maxA = 0;
  for (int i = 0; i < n; i++) {
    cin >> a >> b[i];
    maxA = max(a, maxA);
  }
  long long int sum = 0, sumB = 0;
  for (int i = 0; i < n; i++) {
    if (maxA < b[i]) {
      sum++;
      sumB += b[i];
    }
  }
  if (h - sumB <= 0)
    cout << sum << endl;
  else if ((h - sumB) % maxA > 0)
    cout << sum + (h - sumB) / maxA + 1 << endl;
  else
    cout << sum + (h - sumB) / maxA << endl;
}
