#include <bits/stdc++.h>
#define int long long
using namespace std;
const int inf=1e9*1e5;
int n,a,b,c; string s;
vector<int> z(string s) {
int n = (int) s.length();
vector<int> z(n);
for (int i = 1, l = 0, r = 0; i < n; ++i) {
if (i <= r)
z[i] = min (r - i + 1, z[i - l]);
while (i + z[i] < n && s[z[i]] == s[i + z[i]])
++z[i];
if (i + z[i] - 1 > r)
l = i, r = i + z[i] - 1;
}
return z;
}
int solve(string s){
int n=s.size();
vector<int> p=z(s),dp(n,inf);
vector<vector<int>> A(n+1);
set<int> cur;
for(int i=1;i<n;i++){
A[p[i]].push_back(i);
cur.insert(i);
}
dp[0]=a;
for(int i=0;i<n;i++){
for(int x:A[i]) cur.erase(x);
if(i) dp[i]=min(dp[i],dp[i-1]+a);
int mx=1;
int last=i;
while(1){
auto it = cur.upper_bound(last);
if(it==cur.end()) break;
last=*it+i;
mx++;
dp[last]=min(dp[last],dp[i]+b+c*mx+a*(last+1-mx*(i+1)));
}
}
return dp.back();
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(nullptr);
//freopen("in.txt","r",stdin);
cin>>n>>s>>a>>b>>c;
reverse(s.begin(),s.end());
int answer=a*n;
for(int i=0;i<n;i++){
string ns;
for(int j=i;j<n;j++)ns+=s[j];
answer=min(answer,solve(ns)+a*i);
}
cout << answer;
}
