Bishop moves

Statement

In chess, the bishop moves diagonally, any number of squares. Given two different squares of the chessboard, determine whether a bishop can go from the first to the second in one move.

The program receives as input four numbers from 1 to 8, specifying the column and row numbers of the starting square and the column and row numbers of the ending square. The program should output YES if a Bishop can go from the first square to the second in one move, or NO otherwise.

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In all the problems input the data using input() and print the result using print().