
int main(int argc, char* argv[])
{
	int i,j,n;
	char s[32];
	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)))
				break;
		}
		if(s[j]!='\0')
		{
			printf("no\n");
		}
		else
		{
			printf("yes\n");
		}
	}
	return 0;
}

