121-Problem mate in 2 solution.

Solution: 1. Bg1-f2! waiting
 1. ... Sf8 ad lib 2. Sg7(x)e6#
 1. ... Sf5 ad lib 2. e3-e4#
 1. ... Sf5-d4 2. e3xd4#
 1. ... Sf5xe3 2. Bf2xe3#