i := 1;
//m - stulpeliu sk.
//n - eiluciu sk.
while (i <= n) do
begin
	z := 1;
	while (z <= m)
	begin
		if (i = z) AND (mas[i,z] <> 1) then vienetine := 0
		else if (mas[i,z] <> 0) then vienetine := 0;
		z := z+1;
	end;
	i := i+1;
end;

if (vienetine = 0) then writeln('matrica nera vienetine')
else writeln('matrica yra vienetine');