
int main()
{
 int n,i,j;
 char **string;
 scanf("%d", &n);
 //??????
 string=(char**)malloc(sizeof(char*)*n);
 for (i=0;i<n;i++)
 {
  string[i]=(char*)malloc(sizeof(char)*20);
  scanf("%s",string[i]);//??????????????????
 }
 
 for (i=0;i<n;i++)
 {
  if (!((string[i][0]>='A' && string[i][0]<='Z') ||
    (string[i][0]>='a' && string[i][0]<='z') ||
    string[i][0]=='_'))//??????????????????????????
  {
   printf("no\n");
   continue;
  }
  for (j=1;string[i][j];j++)//????????????string[i][j]?0??false?for?????
  {
   if (!((string[i][j]>='0' && string[i][j]<='9') ||
    (string[i][j]>='A' && string[i][j]<='Z') ||
    (string[i][j]>='a' && string[i][j]<='z') ||
    string[i][j]=='_'))//??????????????????
   {
    j=0;
    break;
   }
  }
  if (j) printf("yes\n");
  else printf("no\n");
 }
 
 //??????
 for (i=0;i<n;i++)
  free(string[i]);
 free(string);
 return 0;
}
