#include <bits/stdc++.h>
using namespace std;

ifstream fin("energii.in");
ofstream fout("energii.out");

int n, w, egi, cgi, minn;

int main()
{
    int i;
    fin >> n >> w;
    minn = INT_MAX;
    for (i = 1; i <= n; i++)
    {
        fin >> egi >> cgi;
        if (egi >= w && cgi < minn) minn = cgi;
    }
    fout << minn<< "\n";
    return 0;
}