#include<stdio.h>
#include<string.h>
    int main(){
        char signal[10];
        scanf("%s", signal);
        if(strcmp(signal,"Red") == 0){
            printf("Stop\n");
        }
        else if(strcmp(signal, "Yellow") == 0){
            printf("Go\n")
        }
        else{
            printf("Invalid input\n");
        }
        return 0;
    }