

int main()

{
    int n,i,j,point,flag;
    scanf("%d",&n);
char*lab=(char*)malloc(n*20*sizeof(char));
for(i=0;i<n;i++)
    scanf("%s",lab+i*20);
/*for(i=0;i<n;i++)
    puts(lab+i*20);*/
for(i=0;i<n;i++)
{

    for(j=0,flag=0;*(lab+20*i+j)!='\0';j++)
        {
        point=20*i+j;
        if(j==0)
               {
            if (*(lab+point)=='_'||(*(lab+point)>='A'&&*(lab+point)<='Z')||(*(lab+point)>='a'&&*(lab+point)<='z'))
                continue;
                else { //printf("%c\ni is %d\nj is %d\n",*(lab+point),i,j);
                        flag=1;
                        break;
                     }
                }
            else
                if( !((*(lab+point)>='A'&&*(lab+point)<='Z')||(*(lab+point)>='a'&&*(lab+point)<='z'))&& *(lab+point)!='_'   &&  !(*(lab+point)>='0'&&*(lab+point)<='9'))
                    {//printf("%c\ni is %d\nj is %d\n",*(lab+point),i,j);
                        flag=1;
                        break;
                    }
        }
    // printf("flag is %d",flag);
     if(flag)
        printf("no\n");
     else
        printf("yes\n");
}
return 0;
}
