#include "bits/stdc++.h"
#define REP(i,n,N) for(ll i=(n); i<(N); i++)
#define RREP(i,n,N) for(ll i=(N-1); i>=n; i--)
#define CK(n,a,b) ((a)<=(n)&&(n)<(b))
#define ALL(v) (v).begin(),(v).end()
#define p(s) cout<<(s)<<endl
#define p2(a,b) cout<<(a)<<" "<<(b)<<endl
#define v2(T) vector<vector<T>>
typedef long long int ll;
using namespace std;
const ll inf=1e18;

ll N,C,V;
ll dp[101010];
int main(){
    while(cin>>N>>C>>V) {
        REP(i, 0, 101010) dp[i] = inf;
        dp[1] = 0;
        REP(i, 1, N) {
            ll c = dp[i] + C + V;
            for (int x = i * 2; x < 101010; x += i) dp[x] = min(dp[x], c), c += V;
        }

        ll ans = inf;
        REP(i, N, 101010) ans = min(ans, dp[i]);
        p(ans);
    }
    return 0;
}