#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using ll = long long;
#define rep(i,n) for(int i=0;i<(int)(n);i++)

int main(){
	int n,w;
	cin>>n>>w;
	int ans=-1;
	rep(i,n){
		int v,d;
		cin>>v>>d;
		if(d>w) continue;
		ans=max(ans,v);
	}
	cout<<ans<<endl;
}