import sys
import math
from collections import deque,Counter
#sys.setrecursionlimit(10**7)
int1=lambda x: int(x)-1

inp=lambda :int(input())
mi=lambda :map(int,input().split())
li=lambda :list(mi())
mi1=lambda :map(int1,input().split())
li1=lambda :list(mi1())
mis=lambda :map(str,input().split())
lis=lambda :list(mis())
pr=print

from collections import defaultdict
"""
#初期値 0
d=defaultdict(int)

#初期値 1
d=defaultdict(lambda:1)
"""

mod=10**9+7
Mod=998244353
INF=10**18
ans=0

n,h,w=mi()
x=n//2
y=n-x
ans+=(w+h-2)*x*y
print(ans)