#include <bits/stdc++.h>
using namespace std;
//#include <atcoder/all>
//using namespace atcoder;
//using mint = modint1000000007;
//using mint = modint998244353;
std::chrono::time_point<std::chrono::steady_clock> start;
template <typename T> bool chmax(T &u, const T z) { if (u < z) {u = z; return true;} else return false; }
template <typename T> bool chmin(T &u, const T z) { if (u > z) {u = z; return true;} else return false; }
#define ll long long
#define rep(i, n) for (ll i = 0; i < (ll)(n); i++)
typedef pair<ll, int> P;
ll gcd(ll x, ll y) { return y ? gcd(y, x % y) : x; }
ll lcm(ll a, ll b){return a * b / gcd(a, b);}

int main(){
  ll d,a,b;
  cin>>d>>a>>b;
  ll ans=LLONG_MAX;
  rep(i,d+1){
    ans=min(ans,i*a+(d-i)*b);
  }
  cout<<ans<<endl;
  return 0;
}