#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000001
#define Inf64 4000000000000000001
long long N,A,B;

int main() {
	
	
	cin>>N>>A>>B;
	if(N%2==0){
		
		long long ans = Inf64;
		ans = min(ans,A*(N-1) - B*N);
		long long t = N/2;
		ans = min(ans,-A*t);
		if(N>=3)ans = min(ans,-A*((t-1)*2) - B * 2);
		cout<<ans<<endl;
		return 0;
	}
	long long ans = Inf64;
	ans = -N * B + A * (N-1);
	long long t = ans;
	t += (N/2) * (2*B-A*4);
	ans = min(ans,t);
	cout<<ans<<endl;
	
    return 0;
}