#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  long long h;
  cin.tie(0);
  ios::sync_with_stdio(false);
  cin >> n >> h;
  vector<long long> a(n), b(n);
  for (int i = 0; i < (int)(n); ++i) {
    cin >> a[i] >> b[i];
  }
  long long ma = *max_element(a.begin(), a.end());
  long long sum = 0;
  int cnt = 0;
  for (int i = 0; i < (int)(n); ++i) {
    if (b[i] > ma) {
      sum += b[i];
      cnt++;
    }
  }
  h -= sum;
  if (h <= 0) {
    cout << cnt << endl;
  } else {
    cout << cnt + (h + ma - 1) / ma << endl;
  }
  return 0;
}
