#include <bits/stdc++.h>
using namespace std;
long long a[100000], b[100000];
long long dp = 0;
int main() {
  int n;
  long long h;
  cin >> n >> h;
  for (int i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
  }
  sort(a, a + n);
  sort(b, b + n);
  long long j = n;
  while (h > 0) {
    if (j < 1) break;
    if (a[n - 1] >= b[j - 1]) {
      if (h % a[n - 1] == 0)
        dp += h / a[n - 1];
      else
        dp += h / a[n - 1] + 1;
      h = 0;
    } else {
      h -= b[--j];
      dp++;
    }
  }
  cout << dp << endl;
  return 0;
}
