//
//  main.c
//  Track 79,???C???
//
//  Created by Charles.thRay.Lee on 2/1/13.
//  Copyright (c) 2013 Peking University. All rights reserved.
/*
 ??	???? ???? 06 ????? ????
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 ??n????????????????????C?????????????????????C????????
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 ??????n???n?????????????????????????????20?
 ????
 ?????????????C????????????yes?????no?
 ????
 6
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cGB8nd97F3
RKPEGX9R;TWyYcp
iefZIko1s}zy9XBg
sapOF3
6Lv5BYPeLPJ3vV`2[h
 ????
 yes
 
 yes
 
 no
 
 no
 
 yes
 
 no
 ??
 ??????????
 
 ??:???????????????? &#8226; ??:
 ??????????????,????????? ??????
 ?????(????)
 ???????(????????)  ??:????,??????32???
?:???????????
sum Sum M.D.John day Date 3days student_name #33 lotus_1_2_3
char a>b _above $123
*/


int main()
{
    int n,i,i1,k=1;
    long len;
    scanf("%d",&n);
    char s[500][20];
    
    for (i=0; i<n; i++) {
        scanf("%s",s[i]);
        k=1;
        if ((s[i][0]<'A'||s[i][0]>'Z')&&(s[i][0]<'a'||s[i][0]>'z')&&s[i][0]!='_') {
            printf("no\n");
            continue;
        }
        len=strlen(s[i]);
        for (i1=1; i1<len; i1++) {
            if ((s[i][i1]<'A'||s[i][i1]>'Z')&&(s[i][i1]<'a'||s[i][i1]>'z')&&s[i][i1]!='_'&&(s[i][i1]<'0'||s[i][i1]>'9'))
            {
                printf("no\n");
                k=0;
                break;
            }
        }
        if (k==1) {
            printf("yes\n");
        }
    }
    
}
