#include <bits/stdc++.h>
using namespace std;
using i64 = int64_t;
using vi = vector<i64>;
using vvi = vector<vi>;

int main() {
    i64 n, c, v;
    cin >> n >> c >> v;
    vi dp(2 * n, 1e18);
    dp[1] = 0;
    for (int i = 1; i < 2 * n; i++) {
        for (int j = 1; i * j < 2 * n; j++) {
            dp[i * j] = min(dp[i * j], dp[i] + c + v * (j - 1));
        }  
    }
    i64 ans = 1e18;
    for (int i = n; i < 2 * n; i++) {
        ans = min(ans, dp[i]);
    }
    cout << ans << endl;
}