#include <bits/stdc++.h>
using namespace std;
int main(void){
    int n, h; cin >> n >> h;
    int a = 0, b[n];
    for(int i=0; i<n; i++){
        int t;
        cin >> t >> b[i];
        a = max(t, a);
    }
    sort(b, b+n);
    
    int p = n-1;
    while(b[p]>a && h>0)
        h -= b[p--];
    cout << n-1-p+(h>0?(h+a-1)/a:0) << endl;
}
