//source: https://oj.uz/problem/view/JOI22_copypaste3
#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <chrono>
#include <cstdio>
#include <deque>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <memory>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <tuple>
using namespace std;
#define int long long
#define P pair
#define pi P<int,int>
#define f first
#define s second
#define mp make_pair
#define all(x) begin(x), end(x)
#define sz(x) (int) (x).size()
#define V vector
#define vi V<int>
#define v2i V<vi>
#define v3i V<v2i>
#define vpi V<pi>
#define vb V<bool>
#define v2b V<vb>
#define pb push_back
#define S set
#define si S<int>
#define ins insert
#define era erase
#define M map
#define mii M<int,int>
#define Q queue
#define PQ priority_queue
const int MOD=1e9+7;
const int INF=1e18;
int smax(int& a, int b) {return a = max(a,b);}
int smin(int& a, int b) {return a = min(a,b);}
struct stringmatch {
int n;
int p = 29;
int MOD = 1420696969;
vector<int> pref, ppow;
stringmatch() {}
stringmatch(vector<int> arr) {
n = arr.size();
ppow.push_back(1);
for (int i = 0; i < n+5; i++) {
ppow.push_back((p * ppow[i])%MOD);
}
pref.push_back(0);
for (int i = 0; i < n; i++) {
pref.push_back((pref[i] + (arr[i]+1)*ppow[i])%MOD);
}
}
bool equiv(int l1, int r1, int l2, int r2) {
if (r1 - l1 != r2 - l2) return 0;
if (l1 > l2) {
swap(l1, l2);
swap(r1, r2);
}
int sub1 = (pref[r1+1] - pref[l1] + MOD)%MOD;
int sub2 = (pref[r2+1] - pref[l2] + MOD)%MOD;
sub1 *= ppow[l2-l1]; sub1 %= MOD;
return (sub1 == sub2);
}
};
int n;
vi s;
int a, b, c;
v2i dp, nxt;
stringmatch sm;
signed main() {
ios::sync_with_stdio(false); cin.tie(nullptr);
cin >> n;
for (int i = 0; i < n; i++) {
char c; cin >> c; s.pb(c - 'a');
}
cin >> a >> b >> c;
sm = stringmatch(s);
nxt = v2i(n, vi(n, -1));
for (int l = 0; l < n; l++) {
for (int r = l; r < n; r++) {
for (int sf = r-l+1; r + sf < n; sf++) {
if (sm.equiv(l, r, l+sf, r+sf)) {
nxt[l][r] = l + sf;
break;
}
}
}
}
dp = v2i(n, vi(n, INF));
for (int i = 0; i < n; i++) {
dp[i][i] = a;
}
for (int l = n-1; l >= 0; l--) {
for (int r = l; r < n; r++) {
//add letters
if (r+1 < n) {
smin(dp[l][r+1], dp[l][r]+a);
}
if (l > 0) {
smin(dp[l-1][r], dp[l][r]+a);
}
//copy + paste
int cost = dp[l][r] + b + c;
int cl = l; int cr = r;
while (nxt[cl][cr] != -1) {
int nl = nxt[cl][cr];
int nr = nl + r - l;
cost += a * (nl - cr - 1);
cost += c;
smin(dp[l][nr], cost);
cl = nl; cr = nr;
}
}
}
cout << dp[0][n-1];
return 0;
}
