#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
const long long mod=998244353;
const long long mod2=469762049;
int main(){
    cin.tie(0)->sync_with_stdio(0);
    cout.tie(0);
    int N;
    ll M;
    cin>>N>>M;
    ll a[N+1],b[N+1];
    for(int i=1;i<=N;i++) cin>>a[i]>>b[i];
    vector<ll>border;
    for(int i=1;i<=N;i++){
        int k=M-a[i];
        k/=b[i];
        k++;
        border.push_back(k);
    }
    sort(border.begin(),border.end());
    int l=1,r=N+1;
    while(l!=r){
        int m=(l+r)/2;
        bool ok=1;
        int day=0;
        //cout<<m<<"  ";
        for(int i=0;i<N;i++){
            if(i%m==0) day++;
            if(border[i]<day) ok=0;
            //cout<<border[i]<<":"<<day<<" ";
        }
        //cout<<endl;
        if(ok) r=m;
        else l=m+1;
    }
    cout<<l<<"\n";
}