Given six sticks, two of length A metres, two of length B metres and two of length C metres. Find the maximum area of the rectangle which can be formed using four sticks from these six sticks.

INPUT
A single line containing three integers A, B and C.

OUTPUT
The maximum area of the rectangle which can be formed using four sticks from these six sticks

CONSTRAINTS
1 <= A, B, C <= 100

SAMPLE INPUT
1 2 3

SAMPLE OUTPUT
6