#include <bits/stdc++.h>
using namespace std;
int main() {
  long long counter1, counter2, a, b;
  counter1 = 0;
  counter2 = 0;
  long long N, H;
  cin >> N >> H;
  if (N == 1) {
    cin >> a >> b;
    counter2 = 1;
    H -= b;
    if (H % a > 0) {
      cout << counter2 + H / a + 1 << endl;
    } else {
      cout << counter2 + H / a << endl;
    }
  } else {
    priority_queue<long long> aa;
    priority_queue<long long> bb;
    for (long long i = 0; i < N; i++) {
      cin >> a >> b;
      aa.push(a);
      bb.push(b);
    }
    counter1 = aa.top();
    while (H > 0) {
      if (bb.top() <= counter1) {
        break;
      } else
        H = H - bb.top();
      bb.pop();
      counter2++;
    }
    if (H > 0 && H % counter1 > 0) {
      cout << counter2 + (H / counter1) + 1 << endl;
    } else if (H > 0 && H % counter1 == 0) {
      cout << counter2 + (H / counter1) << endl;
    } else {
      cout << counter2 << endl;
    }
  }
}
