#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <numeric>
#include <bitset>
#include <cmath>
#include <limits>

static const int MOD = 998244353;
using ll = long long;
using uint = unsigned;
using ull = unsigned long long;
using namespace std;

template<class T> constexpr T INF = ::numeric_limits<T>::max() / 32 * 15 + 208;

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