#include <bits/stdc++.h>
using namespace std;

typedef long long ll; 

int main(){
  ll n,h; cin >> n >> h;
  vector<ll> a(n),b(n);
  for(int i=0;i<n;i++) cin >> a[i] >> b[i];
  sort(a.begin(),a.end());
  sort(b.begin(),b.end());
  ll m = a[n-1];
  ll sum = 0,t=0;
  for(int i=0;i < n && b[n-i-1] > m && sum < h; i++){t++;sum = sum + b[n-i-1];}
  if(sum < h) t += (h - sum) / m  + ((h-sum)%m == 0 ? 0 : 1);
  cout << t << endl;
  return 0;
}
  

  
