#include <bits/stdc++.h>
using namespace std;

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int N,M; cin >> N >> M;
    vector<int> D(N);
    for(auto &d : D){
        int a,b; cin >> a >> b;
        d = (M-a)/b+1;
    }
    sort(D.begin(),D.end());
    int answer = 0;
    for(int i=0; i<N; i++){
        int d = D.at(i);
        answer = max(answer,(i+d)/d);
    }
    cout << answer << "\n";
}