def _HPERM_OP(a):
 t = (((a << 18) ^ a) & 3435921408)
 return ((a ^ t) ^ ((t >> 18) & 16383))

def _HPERM_OP ( a ) : t = ( ( ( a << 18 ) ^ a ) & 3435921408 ) return ( ( a ^ t ) ^ ( ( t >> 18 ) & 16383 ) )
clever bit manipulation .