#include <bits/stdc++.h>
using namespace std;
int main(){
  int v[100005],s,d,t[100005],f=0,g=0;
  cin>>s>>d;
  for(int i=1;i<=s;i++){
    cin>>v[i]>>t[i];
    if((d-t[i])*v[i]>f){
      f=(d-t[i])*v[i];
      g=i;
    }
  }
  cout<<g;
}

(https://www.luogu.com.cn/problem/P9569?contestId=124047)