#include<iostream>
#include<vector>
#include<algorithm>
#include<bits/stdc++.h>
#include<math.h>
#include <numeric>
#include<map>
#include<queue>
#include<deque>
#include <bitset>
#include<stack>
#include<set>
#define int long long
using namespace std;
#define all(x) (x).begin(),(x).end()
#define rep(i,n) for (int i=0;i<(n);++i)
#define prep(i,n) for (int i=1;i<=(n);++i)
int INF = 900000000000000;
int mod=998244353;

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