#include <bits/stdc++.h>
using namespace std;
int max(int a[], int n) {
  int ans = 0;
  for (int i = 0; i < n; i++) {
    if (ans < a[i]) {
      ans = a[i];
    }
  }
  return ans;
}
int main() {
  int n, h;
  int count = 0;
  cin >> n >> h;
  int rest = h;
  int a[n], b[n];
  for (int i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
  }
  int m = max(a, n);
  for (int i = 0; i < n; i++) {
    if (m < b[i]) {
      rest = rest - b[i];
      count += 1;
      if (rest <= 0) {
        cout << count << endl;
        return 0;
      }
    }
  }
  if (rest % m == 0) {
    count = count + rest / m;
  } else {
    count = count + rest / m + 1;
  }
  cout << count << endl;
}
