#include <stdio.h>
#include <string.h>
int main()
{
   char s[20];
   scanf("%s"'s);
   if(strcmp(s,"red")==0)
   printf("stop");
   else if(strcmp(s,"yellow")==0)
   printf("Ready");
   else if(strcmp(s,"Green")==0)
   printf("Go");
   else
   printf("Invalid input");
   return 0;
}