#include <bits/stdc++.h>
#define ll long long
#define INF 1000000005
#define MOD 1000000007
#define EPS 1e-10
#define rep(i,n) for(int i=0;i<(int)n;++i)
#define each(a, b) for(auto (a): (b))
#define all(v) (v).begin(),(v).end()
#define zip(v) sort(all(v)),v.erase(unique(all(v)),v.end())
#define fi first
#define se second
#define pb push_back
#define show(x) cout<<#x<<" = "<<(x)<<endl
#define spair(p) cout<<#p<<": "<<p.fi<<" "<<p.se<<endl
#define svec(v) cout<<#v<<":";rep(kbrni,v.size())cout<<" "<<v[kbrni];cout<<endl
#define sset(s) cout<<#s<<":";each(kbrni,s)cout<<" "<<kbrni;cout<<endl
#define smap(m) cout<<#m<<":";each(kbrni,m)cout<<" {"<<kbrni.first<<":"<<kbrni.second<<"}";cout<<endl

using namespace std;

typedef pair<int,int>P;

const int MAX_N = 500005;

int dp[2*MAX_N];

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n;
    cin >> n;
    int c,v;
    cin >> c >> v;
    rep(i,2*n){
        dp[i] = INF;
    }
    dp[1] = 0;
    for(int i=1;i<n;i++){
        int j = 2;
        while(1){
            dp[i*j] = min(dp[i*j],dp[i]+c+(j-1)*v);
            if(i*j >= n){
                break;
            }
            j++;
        }
    }
    int ans = INF;
    for(int i=n;i<2*n;i++){
        ans = min(ans,dp[i]);
    }
    cout << ans << endl;
    return 0;
}