Spell

XORin wants to learn a new spell use it against his evil enemies. Witch Ephie tells him she'll teach him a new spell and gives him 4 numbers. XORin can learn several spells from this numbers which have different powers depending on the order of the numbers. The power of a spell can be obtained in the following way: a*b+c*d. Help XORin rearange the numbers so that the power of the spell is maximum.

Input

On the first line of the input will be 4 numbers.

Output

Print the maximum power of the spell that XORin can obtain.

Constraints

All numbers will be greater than 0 All numbers will be smaller than 100

Sample

Input	Output
1 4 3 2	14

Note

The best arrangement we can obtain is 4*3+2*1=14