#include <bits/stdc++.h>
using namespace std;
using vi = vector<int>;
using vii = vector<vi>;
using pii = pair<int, int>;
using vpii = vector<pii>;
int main() {
  long long int n, h;
  cin >> n >> h;
  long long int a;
  vector<long long int> b(n);
  long long int m = 0;
  for (int i = 0; i < (int)(n); i++) {
    cin >> a >> b[i];
    m = max(a, m);
  }
  sort(b.begin(), b.end());
  long long int c = 0;
  int k = n - 1;
  while (h > 0) {
    if (k < 0) break;
    if (a >= b[k - 1]) {
      h -= a;
      c++;
    } else {
      h -= b[k - 1];
      k--;
      c++;
    }
  }
  while (h > 0) {
    h -= a;
    c++;
  }
  cout << c << endl;
}
