// #pragma GCC target("avx2")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define all(a) a.begin(), a.end()
#define sz(x) x.size()
#define yn(p) cout << (p?"Yes":"No") << endl;
using namespace std;
using ll = long long;
using P = pair<int, int>;
#define Pr pair<ll,ll>
#define Tp tuple<ll,ll,ll>
using Graph = vector<vector<int>>;
const int INF = 1000000000;
const int MOD = 1000000007;
const ll llINF = 1000000000000000000;

#include <atcoder/all>
using namespace atcoder;
// #include <boost/multiprecision/cpp_int.hpp>
// using lll = boost::multiprecision::cpp_int;

void solve() {
  ll d, a, b;
  cin >> d >> a >> b;
  ll ans = llINF;
  for (int i = 0; i <= d; ++i) {
    ans = min(ans, i*a + (d - i) * b);
  }
  cout << ans << endl;
}

int main() {
  std::cin.tie(nullptr);
  std::ios_base::sync_with_stdio(false);
  std::cout << std::fixed << std::setprecision(15);
  solve();
  return 0;
}