#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main(){
  int N,H;
  vector<int> sords;
  cin >> N >> H;
  int m=-1;
  for(int i=0;i<N;i++){
    int a,b;
    cin >> a >> b;
    m=max(m,a);
    sords.push_back(b);
  }
  sort(sords.begin(),sords.end(),greater<int>());
  int atk=0;
  for(int i=0;i<N||H<0||sourds[i]>m;i++){
    H-=sords[i];
    atk++;
  }
  if(H>0){
    atk+=H/m;
    if(H%m!=0)atk++;
  }
  cout << atk << endl;
}
