#include <iostream>
#include <algorithm>
#include <vector>
#include <map>
#include <set>
using namespace std;
typedef long long ll;
const ll mod = 1e9 + 7;
#define ml(x,y) ((x*y)%mod)
ll b1 = 53, p1[3003];
ll inv[3003];
ll a, b, c;
ll hsh[3003];
map<ll, ll> dp;
inline ll fsp(ll x, ll b) {
if (b == 0) return 1;
if (b == 1) return x;
ll g = ml(x, x);
g = fsp(g, b / 2);
if (b % 2 == 0) return g;
return (g * x) % mod;
}
inline ll small(ll l,ll r) {
ll sz = r - l + 1;
if (sz == 1) return a;
if (sz == 2) {
ll fr = (hsh[l] - (l == 0 ? 0 : hsh[l - 1])) % mod;
ll sc = (hsh[l + 1] - hsh[l] + mod) % mod;
sc = (sc * inv[1]) % mod;
if (fr == sc) return min(2 * a, a + b + 2 * c);
return 2 * a;
}
ll fr = (hsh[l] - (l == 0 ? 0 : hsh[l - 1])) % mod;
ll sc = (hsh[l + 1] - hsh[l] + mod) % mod;
ll th = (hsh[l + 2] - hsh[l + 1] + mod) % mod;
sc = (sc * inv[1]) % mod;
th = (th * inv[2]) % mod;
if (sc != fr && fr != th && sc != th) return 3 * a;
if (sc == fr && fr == th) return min(3 * a, a + b + 3 * c);
return min(3 * a, 2 * a + b + 2 * c);
}
inline ll getmin(ll l, ll r) {
ll th = hsh[r] - (l == 0 ? 0 : hsh[l - 1]);
th = (th * inv[l]) % mod;
if (dp.find(th) != dp.end()) return dp[th];
if (r - l + 1 <= 3) return small(l, r);
ll dc = 0, tot = (r - l + 1) * a;
for (ll ln = 1; ln <= (r - l + 1) / 2; ++ln) {
if (a * ln <= c) continue;
map<ll, ll> m, d; map<ll, pair<ll, ll>> st;
for (ll i = l; i + ln <= r + 1; ++i) {
ll j = i + ln - 1;
ll hs = (hsh[j] - (i > 0 ? hsh[i - 1] : 0) + mod) % mod;
hs = (hs * inv[i]) % mod;
if (m.find(hs) != m.end()) {
if (i < d[hs]) continue;
}
else st[hs] = { i,j };
d[hs] = i + ln;
++m[hs];
}
for (map<ll, ll>::iterator it = m.begin(); it != m.end(); ++it) {
pair<ll, ll> se = st[it->first];
ll prp = getmin(se.first, se.second);
ll tcost = it->second * ln * a - prp - it->second * c - b;
if (tcost <= 0) continue;
dc = max(dc, tcost);
}
}
dp[th] = tot - dc;
return tot - dc;
}
int main()
{
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
ll n; cin >> n;
string s; cin >> s;
cin >> a >> b >> c;
p1[0] = 1;
p1[1] = b1;
for (ll i = 2; i <= s.size() + 3; ++i) {
p1[i] = (p1[i - 1] * b1) % mod;
}
inv[0] = 1;
for (ll i = 1; i <= s.size(); ++i) {
inv[i] = fsp(p1[i], mod - 2);
}
ll lst = 0;
for (ll i = 0; i < s.size(); ++i) {
hsh[i] = ((s[i] - 95) * p1[i]) % mod;
hsh[i] = (hsh[i] + lst) % mod;
lst = hsh[i];
}
cout << getmin(0, n - 1);
}
