#include<bits/stdc++.h>
using namespace std;
using ll = long long int;
using ld = long double;
#define pow(n,m) powl(n,m)
#define sqrt(n) sqrtl(n)
const ll MAX = 5000000000000000000;
const ll MOD = 0;
void randinit(){srand((unsigned)time(NULL));}
int main(){
    ll d,a,b;
    cin >> d >> a >> b;
    ll ans = MAX;
    for(ll i = 0;i <= d;i++) ans = min(ans,i * a + (d - i) * b);
    cout << ans << endl;
}