#include <bits/stdc++.h>
//#include <atcoder/all>
using namespace std;
//using namespace atcoder;
using ll = long long;
using ld = long double;
//using mint = modint998244353;
int main(){
    ll n,m;
    cin >> n >> m;

    vector<ll> a(n,0);
    vector<ll> b(n,0);
    vector<ll> d(n,0);

    for(ll i = 0; i < n; i++){
        cin >> a[i] >> b[i];
        d[i] = (m-a[i]) / b[i];
        d[i]++;
        //if((m-a[i])%b[i] != 0)d[i]++;
    }

    sort(d.begin(),d.end());

    ll ans = 0;
    for(ll i = 0; i < n; i++){
        ll p  = ((i+1) / d[i]);
        if((i+1) % d[i] != 0)p++;

        if(ans < p)ans = p;
    }

    cout << ans << '\n';


    return 0;
}