my $x = '';
my $c1;
while ( ( $c1 = ReadKey 0 ) =~ m/^[0-9]$/ ) {
    $x .= $c1;
}
my $y = '';
my $c2
while ( ( $c2 = ReadKey 0 ) =~ m/^[0-9]$/ ) {
    $y .= $c2;
}
my $z = '';
my $c3
while ( ( $c3 = ReadKey 0 ) =~ m/^[0-9]$/ ) {
    $z .= $c3;
}