#include <bits/stdc++.h>
using namespace std;
int main(void) {
  vector<long long> a(100000), b(100000);
  long long n, h, max;
  int i;
  long long temp;
  float temp2;
  int count = 0;
  cin >> n >> h;
  for (i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
  }
  max = 0;
  for (i = 0; i < n; i++) {
    if (max < a[i]) {
      max = a[i];
    }
  }
  for (i = 0; i < n; i++) {
    if (max < b[i]) {
      h -= b[i];
      count++;
    }
  }
  if (h > 0) {
    temp = h / max;
    temp2 = (float)h / max;
    count += temp;
    i = (int)temp;
    if (temp2 - i > 0) {
      count++;
    }
  }
  cout << count << endl;
  return 0;
}
