#include <bits/stdc++.h> // #include <atcoder/all> // using namespace atcoder; #define _overload3(_1,_2,_3,name,...) name #define _rep(i,n) repi(i,0,n) #define repi(i,a,b) for(int i=int(a);i<int(b);++i) #define rep(...) _overload3(__VA_ARGS__,repi,_rep,)(__VA_ARGS__) #define rrep(i,n) for(int i=int(n-1);i>=int(0);--i) #define fore(i,a) for(auto &i:a) #define all(x) x.begin(),x.end() #define sz(x) ((int)(x).size()) #define bp(x) (__builtin_popcount((long long)(x))) #define pb push_back #define eb emplace_back #define mp make_pair #define V vector #define P pair<int,int> #define TP tuple<int,int,int> #define F first #define S second template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; } template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; } using ll = long long; using ld = long double; using namespace std; const int INF = 1001001001; const ll INFL = 1001001001001001001; const int MAX = 2e6+1; int main() { ll d;cin>>d; ll a,b;cin>>a>>b; ll ans=INFL; rep(i,d+1){ chmin(ans,a*i+(d-i)*b); } cout<<ans<<endl; return 0; }