#include <bits/stdc++.h>
using namespace std;
int main(){
  int N,H;
  cin >> N >> H;
  int ans = 0;
  vector<int> a(N);
  vector<int> b(N);
  for(int i = 0;i < N;i++)cin >> a[i] >> b[i];
  sort(a.begin(),a.end());
  sort(b.begin(),b.end());
  int maxa = a[N-1];
  for(int i = 1;i <= N;i++){
    if(b[N-i] <= maxa)break;
    ans++;
    H -= b[N-i];
    if(H <= 0)break;
  }
  H = max(H,0);
  ans += (H + maxa -1)/maxa;
  cout << ans << endl;
}