#include<bits/stdc++.h>
using namespace std;
#define int int64_t
const int lim=2510;
int n;
string s;
int dp[lim][lim];
int pws[lim],hsh[lim][lim];
const int mod=(1ll<<61)-1;
int sum(int i,int j){
if(i+j<mod)return i+j;
return i+j-mod;
}
int sub(int i,int j){
if(j<=i)return i-j;
return i-j+mod;
}
int mul(int i,int j){
return __int128_t(i)*j%mod;
}
unordered_map<int,vector<int>>mp[lim];
signed main(){
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
cin>>n;
cin>>s;
int a,b,c;
cin>>a>>b>>c;
for(int i=0;i<n;i++){
for(int j=0;j<n;j++){
dp[i][j]=LLONG_MAX;
}
}
for(int l=0;l<n;l++){
hsh[l][l]=s[l];
for(int r=l+1;r<n;r++){
hsh[l][r]=sum(s[r],mul(hsh[l][r-1],37));
mp[r-l][hsh[l][r]].push_back(r);
}
}
for(int l=n-1;0<=l;l--){
dp[l][l]=a;
int cc=1;
for(int r=l+1;r<n;r++){
if(s[l]==s[r])cc++;
dp[l][r]=a+b+cc*c + a*(r-l+1-cc);
}
for(int r=l+1;r<n;r++){
dp[l][r]=min(dp[l][r],min(dp[l+1][r],dp[l][r-1])+a);
int len=r-l+1;
auto&m=mp[r-l][hsh[l][r]];
auto p=upper_bound(m.begin(),m.end(),r+len-1);
int cur=1;
while(p!=m.end()){
cur++;
dp[l][*p]=min(dp[l][*p],dp[l][r]+b+cur*c+(*p-l+1-cur*len)*a);
p=upper_bound(m.begin(),m.end(),*p+len-1);
}
}
}
cout<<dp[0][n-1]<<'\n';
}
