#include <bits/stdc++.h>
using namespace std;
#define int ll
using ll = long long;
using vi = vector<int>;
using vll = vector<ll>;
using ii = pair<int, int>;
using pl = pair<ll, ll>;
const ll MOD1 = 1e9 + 7;
const ll MOD2 = 1e9 + 9;
ll lpow(ll v, ll e, ll MOD) {
return !e ? 1 : (e & 1) ? lpow(v * v % MOD, e >> 1, MOD) * v % MOD : lpow(v * v % MOD, e >> 1, MOD);
}
ll inv(ll v, ll MOD) { return lpow(v, MOD - 2, MOD); }
struct hshuri {
///TODO: doua moduri
string s;
int n, inv29_1, inv29_2;
vi V1, V2;
hshuri(string s0) : s(s0), n(s0.size()), V1(n, 0), V2(n, 0) {
for(int i = 0; i < n; ++i) {
V1[i] = V2[i] = s[i] - 'a' + 1;
if(i) {
V1[i] = (V1[i - 1] * 29 + V1[i]) % MOD1;
V2[i] = (V2[i - 1] * 29 + V2[i]) % MOD2;
}
}
inv29_1 = inv(29, MOD1);
inv29_2 = inv(29, MOD2);
}
pl operator()(int st, int dr) {
ll re1 = V1[dr], re2 = V2[dr];
if(st) {
re1 = (re1 - V1[st - 1] * lpow(29, dr - st + 1, MOD1) % MOD1 + MOD1) % MOD1;
re2 = (re2 - V2[st - 1] * lpow(29, dr - st + 1, MOD2) % MOD2 + MOD2) % MOD2;
}
// for(int j = st; j <= dr; ++j) {
// cout << s[j];
// }
// cout << " " << re1 << "\n";
return {re1, re2};
}
};
const ll INF = 1e18;
signed main() {
cin.tie(0);
ios_base::sync_with_stdio(0);
int n;
string s;
int a, b, c;
cin >> n >> s >> a >> b >> c;
vector<vi> DP(n, vi(n, INF));
hshuri HSH(s);
for(int i = 0; i < n; ++i) DP[i][i] = a;
for(int len = 1; len <= n; ++len) {
vector<pair<pl, int> > Ord;
for(int i = 0; i + len - 1 < n; ++i)
Ord.push_back({HSH(i, i + len - 1), i});
sort(Ord.begin(), Ord.end());
for(int st = 0; st < (int)Ord.size(); ++st) {
int dr = st;
while(dr + 1 < (int)Ord.size() && Ord[dr + 1].first == Ord[st].first) ++dr;
vi S, Urm(dr - st + 1, -1);
for(int j = st; j <= dr; ++j)
S.push_back(Ord[j].second);
sort(S.begin(), S.end());
{
int p = 0;
for(int i = 0; i < (int)S.size(); ++i) {
while(p + 1 < S.size() && S[p] - S[i] < len) ++p;
if(S[p] - S[i] < len) break;
Urm[i] = p;
}
}
for(int i = 0; i < (int)S.size(); ++i) {
int st0 = S[i], p = S[i], id = i;
int cost0 = b + DP[p][p + len - 1]; /// cost to start
int cost_cur = c;
int vmax = S.back();
while(p < n) {
//printf("Dau update la (%d...%d) cu %d + %d din (%d %d)\n", p, p, cost_cur, cost0, p, p);
DP[st0][p + len - 1] = min(DP[st0][p + len - 1], cost_cur + cost0);
if(Urm[id] == -1) break;
cost_cur += c + a * (S[Urm[id]] - p - len);
id = Urm[id];
p = S[id];
}
}
st = dr;
}
// de propagat chestii
for(int i = 0; i + len < n; ++i) {
DP[i][i + len] = min(DP[i][i + len], DP[i][i + len - 1] + a);
DP[i][i + len] = min(DP[i][i + len], DP[i + 1][i + len] + a);
}
}
cout << DP[0][n - 1] << "\n";
return 0;
}
