#include<fstream>

using namespace std;

int G,W,EG[10001],CG[10001],cost[1000];

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

int	main()	
{	int min;
	
	in>>G;
	in>>W;
if ((G<1001)&&(W<5001))	
{
	min=W;
	
	for( int i=1;i<=G;++i)
		in>>EG[i]>>CG[i];
	
	for( int i=1;i<=G;++i)
		
		if(EG[i]==W)
		{	cost[i]=CG[i];
			if(min>cost[i])
				min=cost[i];
		}
		
		out<<min;
}		
else
	out<<0;
}