#include <iostream>
#include <cstring>
#include <stdio.h>
#include <algorithm>

using namespace std;

const int N = 60;

int n, cnt;
char a[N];

int main()
{
    cin >> n;
    while (n -- )
    {
        if (cnt == 0) getchar();
        cnt ++ ;
        int flag = 1;
        gets(a);

        for (int i = 0; i < strlen(a); i ++ )
        {
            if (a[0] == '_' || isupper(a[0]) || islower(a[0]));
            else
            {
                flag = 0; break;
            }

            if (a[i] == '_' || isupper(a[i]) || islower(a[i]) || (a[i] - '0' >= 0 && a[i] - '0' <= 9));
            else
            {
                flag = 0; break;
            }
        }
        if (!flag) printf("no\n");
        else printf("yes\n");
    }
    return 0;
}