import sys INF = float('inf') #10**20,2**63,float('inf') MOD = 10**9 + 7 MOD2 = 998244353 #from collections import defaultdict def solve(): def II(): return int(sys.stdin.readline()) def LI(): return list(map(int, sys.stdin.readline().split())) def LC(): return list(input()) def IC(): return [int(c) for c in input()] def MI(): return map(int, sys.stdin.readline().split()) #2隅でもよい?四隅に均等に置いた方がいい? N,H,W = MI() h = H-1 w = W-1 Ans = (N//2)*(N//2)*(h+w) if(N%2 == 1): Ans += (N//2)*(h+w) print(Ans) return solve() #sys.setrecursionlimit(10 ** 6)#再帰関数ではコメントにしないこと!!