#include<stdio.h>
#include<string.h>

int main(){
    char singnal[10];
    
    scanf("%s",signal);
    
    if(strcmp(signal, "red") == 0){
        printf("stop\n");
    }
    else if (strcmp(signal,"yellow") ==0){
        printf("ready\n");
    }
    else if (strcmp(signal,"green") ==0){
        printf("Go\n");
    }
    else{
        printf("invalid input\n");
    }
    return 0;
}