n,a,b = map(int,input().split())

# 1,1,1,1,1 ..., 1
ans = a * (n-1) - b * n

# 1,-1,1,-1, ..., 1

if n % 2 == 0:
	ans = min(ans, -a * (n-1))
else:
	ans = min(ans, -a * (n-1) - b)

print(ans)