#include <bits/stdc++.h>
#define pb push_back
#define int long long
#define F first
#define S second
#define sz(a) (int)a.size()
#define pii pair<int,int>
#define rep(i , a , b) for(int i = (a) ; i <= (b) ; i++)
#define per(i , a , b) for(int i = (a) ; i >= (b) ; i--)
#define all(a) a.begin(),a.end()
using namespace std ;
const int maxn = 2600 , mod = 1e9 + 7;
vector <pii> vec[maxn][maxn] ;
vector <int> v[maxn] ;
int par[maxn] ;
int dp[maxn][maxn] , z[maxn] ;
int find(int v){
if(par[v] == v)return v;
return par[v] = find(par[v]);
}
void mrg(int v, int u){
v = find(v) ;
u = find(u) ;
if(v==u)return ;
par[v] = u ;
}
signed main(){
ios::sync_with_stdio(0) ; cin.tie(0);
int n;cin >> n ;
string s;
cin >> s;
s= " " + s ;
int a, b, c;
cin >> a >> b >> c;
rep(i , 1, n){
string t ;;
rep(j ,i ,n){
t += s[j];
}
int len = n-i+1 ;
int l =0 , r =0 ;
rep(i , 0 , len)v[i].clear() ;
rep(j , 1, len-1){
z[j]= 0 ;
if(j < r){
z[j] = min(r-j , z[j-l]) ;
}
while(j+z[j] < len && t[j+z[j]] == t[z[j]])z[j]++;
if(r < j+z[j]){
l = j;
r = z[j]+j ;
}
v[z[j]].pb(j) ;
}
rep(i ,0 , len)par[i] = i ;
rep(j , 1 , len-1){
for(int x : v[j-1]){
mrg(x , x+1) ;
}
int st = 0 , ted =0 ;
while(st < len){
ted++ ;
// cout << i << " " << i+st+j-1 << " : " << j << " " << ted << "<--\n";
vec[i][i+st+j-1].pb({ted , j});
st+=j ;
st = find(st) ;
}
}
}
rep(len , 1, n){
for(int l =1 , r= len ; r <= n ; r++,l++){
dp[l][r] = a+ min(dp[l+1][r] , dp[l][r-1]) ;
for(auto [t , s] : vec[l][r]){
dp[l][r] = min(dp[l][r] , dp[l][l+s-1] + b + c*t + a * (len-t*s)) ;
}
}
}
cout << dp[1][n] << "\n";
}
