In 1954, in a gesture of friendship to mark the 300th anniversary of Ukrainian union with Russia, Soviet Premier Nikita Khrushchev gave Crimea to Ukraine.
Ukraine formed a union with Russia in 1654
If the 300th anniversary of the Ukrainian union with Russia was in 1954, then this must have happened 300 years prior in 1654. The system could likely not compute the years. 
( z1 union :ARG1 ( z2 country :name ( z3 name :op "Ukraine" ) ) :ARG2 ( z4 country :name ( z5 name :op "Russia" ) ) :time ( z6 date-entity :year 1654 ) )