#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int N;
  long long int H;
  long long int a[100001] = {0}, b[100001] = {0};
  long long int amax = 0, bmax = 0, amaxi = 0, bmaxi = 0;
  long long int count = 0;
  cin >> N >> H;
  for (int i = 0; i < N; i++) {
    cin >> a[i] >> b[i];
    if (a[i] > amax) {
      amax = a[i];
    }
  }
  for (int i = 0; i < N; i++) {
    if (b[i] > amax) {
      H -= b[i];
      count++;
    }
  }
  while (true) {
    if (H <= 0) {
      break;
    }
    H -= amax;
    count++;
  }
  cout << count << endl;
  return 0;
}
