#include<bits/stdc++.h>
using namespace std;
int main(){
  int n,h;
  cin>>n>>h;
  vector<vector<int>> ab(n*2,vector<int>(2));
  for(int i=0;i<n*2;i+=2){
    int a,b;
    cin>>a>>b;
    ab.at(i)={a,0};
    ab.at(i+1)={b,1};
  }
  sort(ab.begin(),ab.end());
  int c=0;
  int p=2*n-1;
  while(h>0){
    if(ab.at(p).at(1)){
      c++;
      h-=ab.at(p).at(0);
      p--;
    }else{
      c+=(h+ab.at(p).at(0)-1)/ab.at(p).at(0);
      h=0;
    }
  }
  cout<<c<<endl;
}