\includegraphics{https://static.e-olymp.com/content/23/23e15b85ef99207ef7e8881ee868c8f48b2e823b.jpg} Vlad wants to take for lunch a couple of fruits. He has $a$ different bananas, $b$ different apples and $c$ different pears. In how many ways can he choose $2$ different fruits from available? \InputFile Three non-negative integers are given: $a, b$ and $c$. All integers do not exceed $10^6$. \OutputFile Print the number of ways to choose $2$ different fruits for a lunch.