Multiply it with initial values i . e with F ( 0 ) = 0 , F ( 1 ) = 1 , F ( 2 ) = 1
if ( $ n == 1 ) return $ F [ 0 ] [ 0 ] + $ F [ 0 ] [ 1 ] ; power ( $ F , ( int ) ( $ n / 2 ) ) ; multiply ( $ F , $ F ) ; if ( $ n % 2 != 0 ) multiply ( $ F , $ M ) ;