#include <bits/stdc++.h>

using namespace std;

int main(){
  int N, H;
  cin >> N >> H;
  vector<int> b(N);
  int amax = 0;
  for(int i=0;i<N;i++){
    int a;
    cin >> a >> b[i];
    amax = max(a, amax);
  }
  sort(b.begin(), b.end(), greater<int>());
  int ans = 0;
  for(auto&& x:b){
    if(H <= 0)break;
    if(x <= amax)break;
    H -= x;
    ans++;
  }
  if(H > 0)ans += (H + amax - 1) / amax;
  cout << ans << endl;
}