#include<stdio.h>
#include<string.h>
void main()
{
int t,i,j;
char ch[55];
scanf("%d%*c",&t);
for(i=0;i<t;i++)
{
gets(ch);
j=0;
if((ch[0]>='A'&&ch[0]<='Z')||(ch[0]<='z'&&ch[0]>='a')||(ch[0]=='_'))
{
j=1;
for(;ch[j]!='\0';j++)
{
ch[j-1]='\0';
if(ch[j]<='Z'&&ch[j]>='A')
continue;
else if(ch[j]<='z'&&ch[j]>='a')
continue;
else if(ch[j]<='9'&&ch[j]>='0')
continue;
else if(ch[j]=='_')
continue;
else
break;
}
if(ch[j]=='\0')
printf("yes\n");
else
printf("no\n");
}
else
printf("no\n");
}
}