#include <stdio.h>

int main()
{
	long long N, A, B;
	scanf("%lld %lld %lld", &N, &A, &B);
	
	long long ans[2];
	ans[0] = A * (1 - N) - B * (N % 2);
	ans[1] = A * (N - 1) - B * N;
	if (ans[0] < ans[1]) printf("%lld\n", ans[0]);
	else printf("%lld\n", ans[1]);
	fflush(stdout);
	return 0;
}