#include <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<int>>;
const long long X = 1000000000 + 7;
const long long H = 1000000009;
const long long N = 100009;
int main() {
  int n;
  long long h;
  cin >> n >> h;
  long long A = -1;
  vector<long long> B;
  for (int i = 0; i < (int)(n); i++) {
    long long a, b;
    cin >> a >> b;
    A = max(A, a);
    if (A < b) B.push_back(b);
  }
  sort(B.begin(), B.end(), greater<long long>());
  int ans = 0;
  for (auto b : B) {
    if (A < b) {
      h -= b;
      ans++;
    }
    if (h <= 0) break;
  }
  ans += (h + A - 1) / A;
  cout << ans << endl;
}
