#!/bin/sh
read
cnt=0
for i in `echo $REPLY | awk '{for(i=1;i<=NF;i++)print $i}' | sort -n`
do
	cnt=$(( cnt + 1 ))
	eval n$cnt=$i
done
n=$(( $(( $(( n1 % 2 )) + $(( n2 % 2 )) + $(( n3 % 2 )) )) % 2 ))
if [ $n -eq 1 ]
then
	echo $(( n1 * n2 ))
else
	echo 0
fi
