#!/usr/bin/perl
#made by Qajin

$* = 1;
$debug=0;

$c = join('','1'..'9','a'..'z');

$size = 9;
$subsize = sqrt($size);

for($i=0;$i<$size;$i++) {
	$mt .= <>;
}

&fill_matrix($mt);

sub fill_matrix {
	local(@mt) = split("\n",$_[0]);

	local($i);
	local($x,$y,$suppose,$sx,$sy,$sl);
	local($m,$om) = ($_[0],'');

	until($om eq $m || $m !~ / /) {
		$om = $m;
		$sl = $size+1;
		for ($y=0; $y<$size; $y++) {
			for ($x=0; $x<$size; $x++) {
				next if substr($mt[$y],$x,1) ne ' ';

				# rows
				$deny = $mt[$y];

				#columns
				for($i=0; $i<$size; $i++) {
					$deny .= substr($mt[$i],$x,1);
				}

				#sub-matrix
				for($i=0; $i<$subsize; $i++) {
					$deny .= substr($mt[$y-$y%$subsize+$i],$x-$x%$subsize,$subsize);
				}

				$deny =~ s/ //g;
				$possible = substr($c,0,$size);
				$possible =~ s/[$deny]//g if $deny ne '';

				$l = length($possible);
				if ($l == 1) {
					substr($mt[$y],$x,1) = $possible;
				} elsif ($l < $sl) {
					($sx,$sy,$sl,$suppose) = ($x,$y,$l,$possible);
				}
			}
		}
		$m = join("\n",@mt);
		print $m,"\n---\n" if $debug == 1;
	}

	if ($m !~ / /) {
		print $m,"\n---\n";
		return;
	}

	for($i=0;$i<$sl;$i++) {
		substr($mt[$sy],$sx,1) = substr($suppose,$i,1);
		printf "suppose %s in (%d,%d)\n",substr($suppose,$i,1),$sx,$sy if $debug == 1;
		&fill_matrix(join("\n",@mt));
	}
}