start = [[0, 8, 0, 0, 2, 0, 5, 6, 0],
        [0, 0, 0, 1, 0, 0, 0, 0, 7],
        [0, 0, 0, 0, 0, 0, 0, 0, 0],
        [0, 5, 0, 0, 9, 0, 4, 0, 8],
        [0, 0, 7, 8, 0, 0, 0, 0, 3],
        [0, 9, 0, 0, 1, 0, 0, 5, 0],
        [2, 0, 4, 0, 0, 0, 8, 0, 0],
        [0, 6, 0, 0, 8, 5, 0, 0, 0],
        [0, 0, 0, 2, 0, 0, 1, 0, 0]]


def isfine(feld, x, y):
	for (int yi = 0; yi < 9; yi++):
		if (yi != y && feld[x][yi] == feld[x][y]):
			return false;
	for (int xi = 0; xi < 9; xi++):
		if (xi != x && feld[xi][y] == feld[x][y]):
			return false;
	x1 = (x / 3) * 3;
	y1 = (y / 3) * 3;
	for (int xk = x1; xk < x1 + 3; xk++):
		for (int yk = y1; yk < y1 + 3; yk++):
			if ((xk!=x || yk!=y) && feld[xk][yk]==feld[x][y]):
				return false;

	return true;
}

def nextone(feld, x, y):
	if (y == 9):
		y = 0; 
		x++;
	if (x == 9):
		return true;
	if (feld[x][y] > 0):
		if (!isfine(feld, x, y)) return false;
		return nextone(feld, x, y + 1);
	else:
		for (feld[x][y] = 1; feld[x][y] <= 9; feld[x][y]++):
			if (!isfine(feld, x, y)) continue;
			if (nextone(feld, x, y + 1)) return true;
	feld[x][y] = 0;
	return false;


tstart = clock();   
if (nextone(start, 0, 0)):
	for (int x = 0; x < 9; x++):

		for (int y = 0; y < 9; y++):
			cout << start[x][y];
			cout << endl;
else:
	print("Unmöglich!");

time1=clock();
print(tstart." - " .time1."*".CLOCKS_PER_SEC)