#pragma GCC optimize("Ofast","O3","unroll-loops")
#pragma GCC target("avx2")
#include<bits/stdc++.h>
using namespace std;
#define int long long
#define all(x) x.begin(),x.end()
#define x first
#define y second
#define endl '\n'
const int K=29,mod=1234567891,INF=1e18;
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
int n;cin>>n;
vector<char> v(n+1);
for(int i=1;i<=n;i++){
cin>>v[i];
}
int A,B,C;cin>>A>>B>>C;
vector<vector<int>> h(n+2,vector<int>(n+2));
for(int i=1;i<=n;i++){
for(int j=i;j<=n;j++){
h[i][j]=h[i][j-1]*K+v[j]-'a'+1;
h[i][j]%=mod;
}
}
vector<vector<int>> dp(n+2,vector<int>(n+2,INF));
for(int i=1;i<=n;i++){
dp[i][i]=A;
}
for(int i=1;i<=n;i++){
for(int j=1;j+i-1<=n;j++){
int k=j+i-1;
dp[j][k]=min({dp[j+1][k]+A,dp[j][k-1]+A,dp[j][k]});
int cnt=1,cnt1=0;
int j1=k+1;
while(j1<=n){
if(j1+i-1<=n&&h[j][k]==h[j1][j1+i-1]){
cnt++;
dp[j][j1+i-1]=min(dp[j][j1+i-1],dp[j][k]+A*cnt1+B+C*cnt);
j1=j1+i;
}
else{
cnt1++;
j1++;
}
}
}
}
/*for(int i=1;i<=n;i++){
for(int j=i;j<=n;j++){
cout<<dp[i][j]<<' ';
}
cout<<endl;
}*/
cout<<dp[1][n]<<endl;
return 0;
}
/*
10 20 30 40 50 49 59 51 59 69 79
10 20 30 40 39 49 41 49 59 69
10 20 30 29 39 31 41 49 59
10 20 30 40 39 49 49 59
10 20 30 40 39 49 59
10 20 30 29 39 49
10 20 30 40 50
10 20 30 40
10 20 30
10 20
10
*/
