#include <stdio.h>
int main (void)
{
  int n,m,i,x,y,max=0;
  scanf ("%d%d",&n,&m);
  for (i=0;i<n;i++)
   {
      scanf ("%d%d",&x,&y);
      
      
       if(y>max) 
       {
          max=y;
        }
        else max=max;
        
        
    
    
  }
  printf ("%d",max);
  system ("pause");
  return 0;
}