#include <bits/stdc++.h>
using namespace std;
const long long MOD = 1000000007ll;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, h;
  cin >> n >> h;
  vector<int> a(n);
  vector<int> b(n);
  int ans = 0;
  int mxa = -1;
  for (int i = 0; i < (int)(n); ++i) {
    cin >> a[i] >> b[i];
    if (mxa < a[i]) mxa = a[i];
  }
  sort((b).begin(), (b).end());
  for (int i = (int)(n)-1; i >= (int)(0); --i) {
    if (mxa < b[i]) {
      h -= b[i];
      ans++;
    }
  }
  ans += ceil((double)h / mxa);
  cout << ans << endl;
  return 0;
}
