#include<bits/stdc++.h>
using namespace std;
void solve(){
int n,a,b,c;string s;
cin >> n >> s >> a >> b >> c;
long long dp[n+1][n+1];
for(int i = 0;i <= n;i++)for(int j = 0;j <= n;j++) dp[i][j] = LONG_LONG_MAX;
dp[0][0]=0;
set<pair<long long, pair<int, int>>> se;
se.insert({0, make_pair(0,0)});
while(!se.empty()){
auto [d, p] = *se.begin();
se.erase(se.begin());
if(p.first==n) {
cout << d << '\n';
return;
}
vector<pair<long long, pair<int,int>>> v;
v.emplace_back(d+a, pair<int,int>{p.first+1,p.second});
v.emplace_back(d+b, pair<int, int>{0, p.first});
if(p.first+p.second<=n) v.emplace_back(d+c, pair<int,int>{p.first+p.second,p.second});
for(auto [D, P] : v){
if(D>=dp[P.first][P.second]) continue;
if(dp[P.first][P.second] != LONG_LONG_MAX) se.erase({dp[P.first][P.second], {P.first,P.second}});
dp[P.first][P.second]=D;
se.insert({D, {P.first,P.second}});
}
}
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
solve();
}
