#include <bits/stdc++.h>
  
using namespace std;
  
#define rep(i,n) REP(i,0,n)
#define REP(i,s,e) for(int i=(s); i<(int)(e); i++)
#define repr(i, n) REPR(i, n, 0)
#define REPR(i, s, e) for(int i=(int)(s-1); i>=(int)(e); i--)
#define pb push_back
#define all(r) r.begin(),r.end()
#define rall(r) r.rbegin(),r.rend()
#define fi first
#define se second
  
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
 
const int INF = 1e9;
const ll MOD = 1e9 + 7;
double EPS = 1e-8;

const int MAX_N = 1e5+10;

ll dp[MAX_N];

int main(){
    int n;
    ll c, v;
    cin >> n >> c >> v;
    rep(i, MAX_N) dp[i] = 1e18;
    dp[1] = 0LL;
    REP(i, 1, n) {
        ll add = c;
        for(int j = i + i; j < MAX_N; j += i) {
            add += v;
            dp[j] = min(dp[j], dp[i] + add);
        }
    }
    ll ans = 1e18;
    REP(i, n, MAX_N) ans = min(ans, dp[i]);
    cout << ans << endl;
    return 0;
}