#include<fstream.h>
long n,max,w,i,f[1002],v[1002];
int main()
{
ifstream in("energii.in");
ofstream out("energii.out");
max=999999;
in>>n;
in>>w;
for(i=1;i<=n;i++)
{
in>>v[i];
in>>f[i];
}
for(i=1;i<=n;i++)
if(v[i]==w&&f[i]<max)
max=f[i];
out<<max;
return 0;
}