int main(){
	char s[21];
	int i,n,j;
	char jg[100];
	scanf("%d",&n);
	for(i=0;i<n;i++){
		scanf("%s",&s);
		for(j=0;s[j]!='\0';j++){
			if((s[j]=='_')||(s[j]>='A'&&s[j]<='Z')||(s[j]>='a'&&s[j]<='z')||(s[j]>='0'&&s[j]<='9'&&j>0)){
				continue;
			}else{
				break;
			}
		}
		jg[i]=s[j];
	}
	for(i=0;i<n;i++){
		if(jg[i]=='\0'){
			printf("yes\n");
		}else{
			printf("no\n");
		}
	}
	return 0;
}