#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;
struct hshuri {
///TODO: doua moduri
string s;
hshuri(string s0) : s(s0) {}
ll operator()(int st, int dr) {
int re = 1;
for(int j = st; j <= dr; ++j)
re = (re * 29 + (s[j] - 'a')) % MOD1;
return re;
}
};
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<ii> 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;
set<int> S;
for(int j = st; j <= dr; ++j)
S.insert(Ord[j].second);
for(auto st0 : S) {
int p = st0 + len - 1;
int cost0 = b + DP[st0][p]; /// cost to start
int cost_cur = c;
while(p < n) {
//printf("Dau update la (%d...%d) cu %d + %d din (%d %d)\n", st0, p, cost_cur, cost0, st0, p);
DP[st0][p] = min(DP[st0][p], cost_cur + cost0);
if(*S.rbegin() <= p) break;
int urm = *S.lower_bound(p + 1);
cost_cur += c + a * (urm - p - 1);
p = urm + len - 1;
}
}
}
// 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;
}
