#define FUNC 
#define NO 0
#define ONLY_VAL_IN_ROW 1
#define ONLY_VAL_IN_COL 2
#define ONLY_VAL_IN_BOX 3
#define ONLY_VAL_IN_CELL 4
#define ALL_DONE 6
#define STUCK 6

#define VAL_MAYBE '?'
#define VAL_NO    '-'
#define VAL_YES   '@' 

#define bool int

// COL must be ROW+1
#define ROW 1000
#define COL 1001
#define BOX 1002