public boolean checkBox(char[][] board, int s, int t) {
		boolean[] has = new boolean[9];
		for(int i = -1; i <= 1; i++)
			for(int j = -1; j <= 1; j++){
				char ch = board[s + i][t + j];
				if(ch != '.') {
					if(has[ch - '1']) return false;
					has[ch - '1'] = true;
				}
			}
		return true;
	}