171-Mate in two SOLUTION.

Solution: 1. Sc6! [2. Re7, Sd4#]
 1... Qf8/e8/h4/f6 2. Sd4#
 1... Qd8/xe5 2. S(x)d8#
 1... Qh7/g7 2. Sd8/d4#
 In this problem, at least one mate in the set play is changed following the key. This maneuver is called MUTATE