int main(){
    int n,special=0;
    int i,j;
    scanf("%d",&n);
    char a[n][22];
    for(i=0;i<n;i++){
        scanf("%s",a[i]);
    }
    for(i=0;i<n;i++){
        for(j=0;a[i][j]!='\0';j++){
        if(a[i][0]>=48&&a[i][0]<=57){
            printf("no\n");
            special++;
            break;
        }
        if(a[i][j]!=95&&(a[i][j]<65||a[i][j]>90)&&(a[i][j]<97||a[i][j]>122)&&(a[i][j]<48||a[i][j]>57)){
            printf("no\n");
            special++;
            break;
        }
        }
        if(special==0){
            printf("yes\n");
        }
        special=0;
    }
    return 0;
}