#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
const ll INF = LLONG_MAX / 4;
#define rep(i, a, b) for(ll i = a; i <(b); i++)
#define rrep(i, a, b) for(ll i = (b)-1; i >= (a); i--)
#define all(a) begin(a),end(a)
bool chmin(auto& a,auto b){return a > b ? a = b,1 : 0;}
bool chmax(auto& a,auto b){return a < b ? a = b,1 : 0;}

int main(){
    cin.tie(0)->sync_with_stdio(0);

    ll n,m;
    cin >> n >> m;
    vector<ll> a(n), b(n);
    rep(i,0,n) cin >> a[i] >> b[i];
    vector<ll> t(n);
    
    rep(i,0,n) {
        t[i] = (m - a[i]) / b[i] + 1;
    }

    sort(all(t));
    int ans = 0;
    rep(i,0,n) {
        cerr << t[i] << " ";
        chmax(ans, (i+1 + t[i]-1) / (t[i]));
    }cerr << endl;
    cout << ans << endl;
}