//Normal

#define _GLIBCXX_DEBUG
#define ll long long
#include <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<int>>;

void print(auto a){
  cout << a;
}

void prints(auto a){
  cout << a << " ";
}

void prints(){
  cout << " ";
}

void printl(auto a){
  cout << a << endl;
}

void printl(){
  cout << endl;
}

void fix(int n){
  cout << fixed << setprecision(n);
}

int main(){
  int D, A, B; cin >> D >> A >> B;
  int ans = 1e9;
  
  for(int i = 0; i <= D; i++){
    int sum = i*A + (D-i)*B;
    
    ans = min(ans, sum);
  }
  
  printl(ans);
  
  return 0;
}