#include <bits/stdc++.h>
using namespace std;
//#include <atcoder/all>
//using namespace atcoder;
typedef long long ll;
typedef unsigned long long ull;
const int MAX = 1e9;
const int MIN = -1*1e9;
const ll MAXLL = 1e18;
const ll MINLL = -1*1e18;
//const ll MOD = 998244353;
//const ll MOD = 1000000007;
int main()
{
    int N,M; cin >> N >> M;
    vector<pair<int,int>> P(N);
    for(int i = 0; i < N; i++)
    {
        cin >> P[i].second >> P[i].first;
    }
    sort(P.begin(),P.end());

    int Ans = -1;
    for(int i = 0; i < N; i++)
    {
        if(P[i].first > M) break;
        Ans = max(Ans,P[i].second);
    }
    cout << Ans << endl;
    return 0;
}