#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

int main() {
  int n;cin>>n;
  long h;cin>>h;
  long a[n],b[n];
  rep(i,n){
    cin>>a[i]>>b[i];
  }
  sort(a,a+n);
  sort(b,b+n);
  reverse(b,b+n);
  
  long cnt=0,res=h;
  rep(i,n) {
    if (res<=0) break;
    if (b[i] < a[n-1]) break;
    cnt++;
    res-= b[i];
  }
  if (res>0) {
    long nd = floor((res-1) / a[n-1])+1;
    cnt += nd;
  }
  cout<<cnt;
}
