#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
using ll = long long;

vector<vector<ll>> matpow(vector<vector<ll>> a, ll x){
    vector<vector<ll>> res(a.size(), vector<ll>(a.size(), 1LL << 60));
    for(int i = 0; i < a.size(); i++) res[i][i] = 0;
    for(; x > 0; x >>= 1){
        if(x & 1){
            vector<vector<ll>> nres(a.size(), vector<ll>(a.size(), 1LL << 30));
            for(int i = 0; i < a.size(); i++){
                for(int j = 0; j < a.size(); j++){
                    for(int k = 0; k < a.size(); k++){
                        nres[i][j] = min(nres[i][j], res[i][k]+a[k][j]);
                    }
                }
            }
            res = nres;
        }
        vector<vector<ll>> na(a.size(), vector<ll>(a.size(), 1LL << 60));
        for(int i = 0; i < a.size(); i++){
            for(int j = 0; j < a.size(); j++){
                for(int k = 0; k < a.size(); k++){
                    na[i][j] = min(na[i][j], a[i][k]+a[k][j]);
                }
            }
        }
        a = na;
    }
    return res;
}

int main(){
    ll n, a, b; cin >> n >> a >> b;
    vector<vector<ll>> mat(2, vector<ll>(2));
    mat[0][0] = a+b;
    mat[0][1] = -a+b;
    mat[1][0] = -a-b;
    mat[1][1] = a-b;
    auto res = matpow(mat, n-1);
    ll ans1 = min(res[0][0]+b, res[0][1]-b);
    ll ans2 = min(res[1][0]+b, res[1][1]-b);
    cout << min(ans1, ans2) << endl;
    return 0;
}