#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
#define fi first
#define se second
#define vi vector<int>
#define vll vector<long long>
#define pii pair<int, int>
#define pll pair<long long, long long>
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
mt19937_64 rng64(chrono::high_resolution_clock::now().time_since_epoch().count());
inline int rand(int l,int r){return uniform_int_distribution<int>(l, r)(rng);}
inline ll rand(ll l,ll r){return uniform_int_distribution<ll>(l, r)(rng64);}
#ifdef DEBUG
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif
struct custom_hash {
    static uint64_t splitmix64(uint64_t x) {
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }
    size_t operator()(uint64_t x) const {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64(x + FIXED_RANDOM);
    }
};
struct pair_hash{
  size_t operator()(const pair<int,int>&x)const{
    return hash<long long>()(((long long)x.first)^(((long long)x.second)<<32));
  }
};
const int MAXN = 2507;
const int INF = 1e9;
const ll XDD = (ll)1e18;
const int P = 313;
const int MOD[2] = {(int)1e9 + 7, (int)1e9 + 9};
ll dp[MAXN][MAXN];
int nxt[MAXN][MAXN];
vector<pair<pii, int>> T[MAXN][MAXN];
ll Pow[MAXN][2];
int n, A, B, C;
string S;
int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(NULL);
    cout.tie(NULL);
    cin >> n;
    cin >> S;
    cin >> A >> B >> C;
    S = "#" + S;
    for(int j = 0; j < 2; j++){
        Pow[0][j] = 1LL;
        for(int i = 1; i < MAXN; i++){
            Pow[i][j] = (ll)Pow[i - 1][j] * P;
            Pow[i][j] %= MOD[j];
        }
    }
    for(int l = 1; l <= n; l++){
        for(int j = 1; j <= n; j++){
            nxt[j][l] = INF;
        }
        ll Hash[2] = {0LL, 0LL};
        for(int j = n - l + 1; j <= n; j++){
            for(int h = 0; h < 2; h++){
                Hash[h] = (ll)Hash[h] + (ll)S[j] * Pow[j - (n - l + 1)][h];
                Hash[h] %= MOD[h];
            }
        }
        map<pll, vi> m;
        m[mp(Hash[0], Hash[1])].pb(n - l + 1);
        for(int j = n - l; j >= 1; j--){
            for(int h = 0; h < 2; h++){
                Hash[h] = (ll)Hash[h] - (ll)S[j + l] * Pow[l - 1][h] % MOD[h] + MOD[h];
                Hash[h] %= MOD[h];
                Hash[h] = (ll)Hash[h] * P + S[j];
                Hash[h] %= MOD[h];
            }
            m[mp(Hash[0], Hash[1])].pb(j);
        }
       // debug(l);
        for(auto &[id, vec] : m){
            //debug(id);
           // debug(vec);
            reverse(all(vec));
            int wsk = sz(vec) - 1;
            for(int j = sz(vec) - 1; j >= 0; j--){
                while(wsk - 1 > j && vec[wsk - 1] >= vec[j] + l){
                    wsk--;
                }
                if(vec[wsk] >= vec[j] + l){
                    nxt[vec[j]][l] = vec[wsk];
                }
            }
        }
    }
    // for(int i = 1; i <= n; i++){
    //     for(int l = 1; l <= n - i + 1; l++){
    //         cout << nxt[i][l] << ' ';
    //     }
    //     cout << '\n';
    // }
    for(int s = 1; s <= n; s++){
        for(int l = 1; l <= n; l++){
            dp[l][s] = XDD;
        }
        for(int l = 1; l <= n - s + 1; l++){
            dp[l][s] = min(dp[l][s - 1], dp[l + 1][s - 1]) + A;
            for(auto [interval, cnt] : T[l][s]){
                dp[l][s] = min(dp[l][s], (ll)A * (s - interval.se * cnt) +(ll)dp[interval.fi][interval.se] + B + cnt * C);
            }
            int curr = nxt[l][s];
            int cnt = 2;
            while(curr != INF){
                T[l][curr - l + s].pb(mp(mp(l, s), cnt));
                cnt++;
                curr = nxt[curr][s];
            }
        }
    }
    cout << dp[1][n] << '\n';
    return 0;
}
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