CellMitosis(DP)

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

ll CellMitosis(int n,int x,int y,int z){
    ll *dp = new ll[n+1];
    dp[0]=0;
    dp[1]=0;

    for(int i=2;i<=n;i++){
        if(i&1){
            dp[i] = min((dp[i-1]+y),dp[(i+1)/2]+x+z);
        }
        else{
            dp[i] = min((dp[i/2]+x),(dp[i-1]+y));
        }
    }

    return dp[n];
}
int main() {

    #ifndef ONLINE_JUDGE
    // for getting input from input.txt
    freopen("input.txt", "r", stdin);
    // for writing output to output.txt
    freopen("output.txt", "w", stdout);
    #endif

     ll n; cin >> n;
     ll x,y,z;

     cin >> x >> y >> z;


     cout << CellMitosis(n,x,y,z) << endl;



    return 0;
}