use warnings; use 5.014; use strict;

sub first_allzero_row_a {
	my($a) = @_;
	my($r, $q, $c, $f, $o);
	$o = -1;
	$r = 0;
	$q = 0;
	while (!$q && $r < @$a) {
		$c = 0;
		$f = 0;
		while (!$f && $c < @{$$a[$r]}) {
			if (0 != ${$$a[$r]}[$c]) {
				$f = 1;
			} else {
				$c++;
			}
		}
		if (!$f) {
			$q = 1;
			$o = $r;
		} else {
			$r++;
		}
	}
	$o;
}

sub first_allzero_row_b {
	my($a) = @_;
	my($r, $q, $o);
	$o = -1;
	$r = 0;
	$q = 0;
	while (!$q && $r < @$a) {
		if (is_allzero($$a[$r])) {
			$q = 1;
			$o = $r;
		} else {
			$r++;
		}
	}
	$o;
}

sub is_allzero {
	my($a) = @_;
	my($c, $f);
	$c = 0;
	$f = 0;
	while (!$f && $c < @$a) {
		if (0 != $$a[$c]) {
			$f = 1;
		} else {
			$c++;
		}
	}
	!$f;
}