# import pypyjit
# pypyjit.set_param('max_unroll_recursion=-1')
from collections import *
from itertools import *
from functools import *
import math,sys
input = sys.stdin.readline


N,A,B = map(int,input().split())
X = (A-B)*N - A
if N%2==0:
    Y = -A*(N-1)
else:
    Y = -A*(N-1)-B

print(min(X,Y))