#include <bits/stdc++.h>

using namespace std;

#define ll long long
#define rep(i, a, n) for (int i = (int)(a); i < (int)(n); i++)
#define rrep(i, n, a) for (int i = (int)(n); i >= (int)(a); i--)

void solve(){
    int ans = -1;
    int n,w; cin >> n >> w;
    rep(i,0,n){
        int v,w1; cin >> v >> w1;
        if(w1 <= w){
            ans = max(ans, v);
        }
    }
    cout << ans;
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int t = 1;
    //cin >> t;
    rep(i,0,t) solve();

    return 0;
}