3
12ajf
fi8x_a
ff  ai_2

no
yes
no

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

using namespace std;

int main()
{
	char a[60];
	int n;
	while (cin >>n)
	{
		getchar();
		while (n--)
		{
			int flag = 0;
			gets(a);
			int p = strlen(a);
			if ( !(a[0] == '_' || (a[0] >='a' && a[0] <='z') ||( a[0] >='A' && a[0] <='Z')))
				cout << "no" <<endl;
			else
			{
				for (int i=1; i<p; i++)
				{
					if ( !(a[i] == '_' || (a[i] >='a' && a[i] <='z') ||( a[i] >='A' && a[i] <='Z') || ( a[i] >= '0'&& a[i] <='9')))
						flag++;
				}
				if (flag==0)
					cout << "yes" << endl;
				else
					cout << "no" << endl;
			}
		}
	}
	return 0;
}