#include<bits/stdc++.h>
using namespace std;
#define ll long long 
ll n,h,a[1000005],b[1000005],sum,maxi,rez,reztot;
int main(){
    cin >> n >> h;
    for(ll i=1;i<=n;i++) cin >> a[i] >> b[i];
    for(ll i=1;i<=n;i++) if(maxi<a[i]) maxi=a[i];
    sort(b+1,b+n+1);
    for(ll i=n;i>=1;i--){
        if(b[i]<=maxi) break;
        if(b[i]>maxi){h-=b[i]; rez++;}
        if(h<=0){ cout<<rez; return 0;}
    }
    while(h>0){h-=maxi; rez++;}
    cout<<rez;
}