#include<stdio.h>
int main()
{
	long long int n, a, b;
	scanf("%lld %lld %lld", &n, &a, &b);
	long long int ans = (n - 1) * a - n * b;
	if (ans > (1 - n) * a - (n % 2) * b)
		ans = (1 - n) * a - (n % 2) * b;
	printf("%lld\n", ans);
	return 0;
}