int main()
{    
    char a[21];
    int i,j,n,k=0;
    int len;
    scanf("%d\n",&n);
    for(i=1;i<=n;i++)
    { 
     k=0;               
     gets(a);
     if (a=="\0") continue;
     len=strlen(a);
     if((a[0]=='_')||((a[0]>='A')&&(a[0]<='Z'))||
     ((a[0]>='a')&&(a[0]<='z')))
     {
	  for(j=1;j<len;j++)
      {
	    if((a[j]=='_')||((a[j]>='A')&&(a[j]<='Z'))||
         ((a[j]>='a')&&(a[j]<='z'))||((a[j]>='0')&&(a[j]<='9')))
         k++;
      }
      if(k==len-1)
       printf("yes\n"); 
      else
       printf("no\n");
      }
     else
      { 
        printf("no\n");
        continue;
      }
     
     }
}