#include <iostream>
#include <vector>

using namespace std;

int main() {
    int N, W;
    cin >> N >> W;
    
    vector<int> capacities(N);
    vector<int> weights(N);

    for (int i = 0; i < N; ++i) {
        cin >> capacities[i] >> weights[i];
    }

    int maxCapacity = -1;
    for (int i = 0; i < N; ++i) {
        if (weights[i] <= W) {
            maxCapacity = max(maxCapacity, capacities[i]);
        }
    }

    cout << maxCapacity << endl;

    return 0;
}