K chess queens (0 ≤ K < M×N) are located on a rectangular chessboard of size M × N (1 ≤ M, N ≤ 26) and there is no more than one queen in each cell. We consider a vacant cell is under attack if it's possible to move into it at least one of the queens with just one move according to the chess rules.

The task is to add one more queen into one of the vacant chessboard cells so that the number of cells under action will be minimal.

The chessboard rows are labeled with lowercase Latin letters starting with a from the bottom; the columns are labeled with numbers starting with 1 from the left. Thus the cells can be labeled as a1, f23, etc.