#include <iostream>
#include <vector>
#include <cmath>
#include <map>
#include <set>
#include <iomanip>
#include <queue>
#include <algorithm>
#include <numeric>
#include <deque>
#include <complex>
#include <cassert>

using namespace std;
using ll = long long;

int main(){

    ll d, a, b, ans=1e18;
    cin >> d >> a >> b;
    for (ll i=0; i<=d; i++) ans = min(ans, i*a+(d-i)*b);
    cout << ans << endl;

    return 0;
}