#include <bits/stdc++.h>
using namespace std;
const long long MOD = 1000000007ll;
const double EPS = 1e-11;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, h, a, b[114514];
  cin >> n >> h;
  int m = 0;
  for (int i = 0; i < (n); ++i) {
    cin >> a >> b[i];
    m = max(m, a);
  }
  sort(b, b + n);
  int cnt = n - 1;
  while (h) {
    if (b[cnt] < m) {
      break;
    }
    h -= b[cnt];
    --cnt;
  }
  cout << n - 1 - cnt + (h > 0 ? (h - 1) / m + 1 : 0) << '\n';
  return 0;
}
