#include<bits/stdc++.h>
using namespace std;
struct p{
    int a;
    int f;
}k[1000000];
bool cmp(p xx,p yy){
    return xx.a>yy.a;
}
int main(){
    int c=0,i,n,h,s=0;
    cin>>n>>h;
    for(i=1;i<=n;i++){
        cin>>k[c++].a;
        k[c].f=1;
        cin>>k[c++].a;
    }
    sort(k,k+c,cmp);
    for(i=0;i<c;i++){
        if(k[i].f==1)
        {
            h-=k[i].a;s++;
            if(h<=0){cout<<s<<endl;return 0;}
        }
        else if(k[i].f!=1){
            if(h%k[i].a==0)s+=h/k[i].a;
            else s+=h%k[i].a+1
            cout<<s<<endl;
            return 0;
        }
    }
}