#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
int main(){
    long long n,h,m=0L,i,a;
    cin>>n>>h;
    vector<long long>b(n);
    for(i=0LL;i<n;i++){cin>>a>>b[i];m=max(m,a);}
    sort(b.rbegin(),b.rend());
    for(i=0LL;h>0&&b[i]>m&&i<n;i++)h-=b[i];
    cout<<(h>0LL?(h+m-1LL)/m:0LL)+i<<endl;
    return 0;
}