#include<bits/stdc++.h>
using namespace std;
int x,y;
int a,b,c;

int main()
{cin>>x>>y;
	while(x--)
	{
		cin>>a>>b;
		if(y>a && b>c)
		{
			c=b;
		}	
	} 
	cout<<c;
	return 0;
}