#pragma GCC target("avx2")
#pragma GCC optimize("03")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
using namespace std; typedef long double ld; typedef long long ll;
typedef unsigned long long ull;
#define endl "\n"
#define FOR(i,a,b) for(int i=(a);i<=(b);i++)
#define rep(i,n) for(int i=0;i<(n);i++)
#define PII pair<int, int>
#define PLL pair<ll, ll>
#define ALL(x) (x).begin(), (x).end()
constexpr int INF=1<<30; constexpr ll LINF=1LL<<60; constexpr ll mod=1e9+7; constexpr int NIL = -1;
template<class T>inline bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T>inline bool chmin(T &a, const T &b) { if (b<a) { a = b; return 1; } return 0; }
template<class T>inline int popcount(T a) {return __builtin_popcount(a);}
template<class T>inline T emod(T a, T p) { return (a%p + p) % p;}
//-------------------
vector<ll> dp(100000+5, LINF);
int main() {
    cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(15);
    int n, c,v; cin >> n >> c >> v;

    dp[1] = 0;
    for(int i=1; i < n; i++) {
        ll cnt = 1;
        for(int j=i*2;j<=2*n; j+=i) {
            chmin(dp[j], dp[i] + c + cnt * v);
            cnt++;
        }
    }
    
    // rep(i, n) cout << dp[i+1] << endl;
    ll ans = LINF;
    FOR(i, n, 2*n) chmin(ans, dp[i]);
    cout << ans << endl;
    return 0;
}