#include<iostream>
#include<string>
#include<algorithm>
#include<cctype>
#include<set>
#include<bitset>
#include<math.h>
#include<map>
#include<queue>
#include<iomanip>
using namespace std;


int main(){
    int d, a, b, x;
    cin >> d >> a >> b;
    if (a <= b) x = d;
    else x = 0;
    cout << x * a + (d - x) * b << endl;
}