#include <bits/stdc++.h>

using namespace std;

#define fst(t) std::get<0>(t)
#define snd(t) std::get<1>(t)
#define thd(t) std::get<2>(t)
#define unless(p) if(!(p))
#define until(p) while(!(p))

using ll = long long;
using P = std::tuple<int,int>;

const int dx[8] = {-1, 1, 0, 0, -1, -1, 1, 1}, dy[8] = {0, 0, -1, 1, -1, 1, -1, 1};

int N, C, V;
int dp[50100];

int main(){
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    std::cin >> N >> C >> V;

    fill(dp, dp+N+1, 1001001001);
    dp[1] = 0;
    
    for(int i=1;i<N;++i){
        for(int j=2;j<=(N+i-1)/i;++j){
            int idx = min(i * j, N);
            dp[idx] = min(dp[idx], dp[i] + C + (j - 1) * V);
        }
    }

    std::cout << dp[N] << std::endl;
}