#include <stdio.h>
#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000001
#define Inf64 1000000000000000001

int main(){
	
	int n,w;
	cin>>n>>w;
	int ans = -1;
	rep(i,n){
		int a,b;
		cin>>a>>b;
		if(b<=w)ans = max(ans,a);
	}
	cout<<ans<<endl;
		
	
	return 0;
}