/* Sample Input 8 7 0 6 9 0 0 0 0 0 0 0 0 0 0 8 6 7 0 1 0 0 5 0 0 0 0 0 0 0 0 0 0 1 0 8 7 8 0 3 0 0 0 0 6 0 0 3 1 8 4 9 0 0 1 0 6 7 0 5 0 0 0 9 3 8 0 0 1 0 0 0 0 0 0 0 0 0 6 0 3 Solution: 8 7 4 6 9 3 5 2 1 3 9 5 4 1 2 8 6 7 6 1 2 8 5 7 3 9 4 4 2 9 5 7 6 1 3 8 7 8 1 3 2 9 4 5 6 5 6 3 1 8 4 9 7 2 1 4 6 7 3 5 2 8 9 9 3 8 2 6 1 7 4 5 2 5 7 9 4 8 6 1 3 */ /*one more difficulty sample input 0 0 0 0 0 9 0 7 0 0 0 0 0 8 2 0 5 0 3 2 7 0 0 0 0 4 0 0 1 6 0 4 0 0 0 0 0 5 0 0 0 0 3 0 0 0 0 0 0 9 0 7 0 0 0 0 0 6 0 0 0 0 5 8 0 2 0 0 0 0 0 0 0 0 4 2 0 0 0 0 8 Solution: 6 8 5 4 3 9 2 7 1 4 9 1 7 8 2 6 5 3 3 2 7 5 6 1 8 4 9 9 1 6 3 4 7 5 8 2 7 5 8 1 2 6 3 9 4 2 4 3 8 9 5 7 1 6 1 3 9 6 7 8 4 2 5 8 6 2 9 5 4 1 3 7 5 7 4 2 1 3 9 6 8 */
/*one with various solutions 0 0 0 0 0 0 0 7 0 0 0 0 0 8 2 0 5 0 3 2 7 0 0 0 0 4 0 0 1 6 0 4 0 0 0 0 0 5 0 0 0 0 3 0 0 0 0 0 0 9 0 7 0 0 0 0 0 6 0 0 0 0 5 8 0 2 0 0 0 0 0 0 0 0 4 2 0 0 0 0 8 */