#include <bits/stdc++.h> 
using namespace std;
using ll =long long;
#define all(v) v.begin(),v.end()
 #define rep(i,a,b) for(int i=a;i<b;i++)
#define rrep(i,a,b) for(int i=a;i>=b;i--)

ll INF=2e18;


int main() {
    ios::sync_with_stdio(false);
  cin.tie(0);
  
  ll N,W;cin>>N>>W;
  ll ans=-1;
  for(ll i=0;i<N;i++) {
    ll v,w;cin>>v>>w;
    if(w<=W) ans=max(ans,v);
  }

  cout<<ans<<endl;
}