#pragma GCC optimize("O3,unroll-loops")
#include <string>
#include <iostream>
#include <map>
#include <cstring>
#include <vector>
#include <algorithm>
using namespace std;
using ll = long long;
template <typename T>
using ve = vector<T>;
template <typename T>
using bs = basic_string<T>;
const int N = 2505;
const ll B = 137, M = 1000000007,
B2 = 141, M2 = 1000000009;
int n;
ll dp[N][N], a, b, c;
char s[N];
ll hs[N], bp[N], ibp[N], bp2[N], ibp2[N], hs2[N];
ll bpow(ll a, ll b, ll m) {
if (!b) return 1;
ll r { bpow(a, b / 2, m) };
if (b & 1) return r * r % m * a % m;
return r * r % m;
}
void do_hash() {
bp[0] = ibp[0] = bp2[0] = ibp2[0] = 1;
for (int i = 1; i <= n; ++i) bp[i] = bp[i - 1] * B % M, ibp[i] = bpow(bp[i], M - 2, M);
for (int i = 1; i <= n; ++i) hs[i] = bp[i] * (s[i] - 'a' + 1) % M, hs[i] = (hs[i] + hs[i - 1]) % M;
for (int i = 1; i <= n; ++i) bp2[i] = bp2[i - 1] * B2 % M2, ibp2[i] = bpow(bp2[i], M2 - 2, M2);
for (int i = 1; i <= n; ++i) hs2[i] = bp2[i] * (s[i] - 'a' + 1) % M2, hs2[i] = (hs2[i] + hs2[i - 1]) % M2;
}
inline ll get_hash(int l, int r) {
return (ibp[l] * (hs[r] - hs[l - 1] + M) % M) * (ibp2[l] * (hs2[r] - hs2[l - 1] + M2) % M2);
}
ve<ll> chocolate;
ve<bs<int>> oo;
int get_pos(int l, int r) {
return lower_bound(chocolate.begin(), chocolate.end(), get_hash(l, r)) - chocolate.begin();
}
void init() {
do_hash();
memset(dp, 63, sizeof dp);
for (int i = 1; i <= n; ++i) {
dp[i][i] = a;
for (int j = i; j <= n; ++j)
chocolate.push_back(get_hash(i, j));
}
sort(chocolate.begin(), chocolate.end());
chocolate.erase(unique(chocolate.begin(), chocolate.end()), chocolate.end());
oo = ve<bs<int>>(chocolate.size());
for (int i = 1; i <= n; ++i)
for (int j = i; j <= n; ++j)
oo[get_pos(i, j)].push_back(i);
}
int main() {
scanf("%d%s%lld%lld%lld", &n, s + 1, &a, &b, &c);
init();
for (int l = 1; l <= n; ++l) {
for (int i = 1, j = l; j <= n; ++i, ++j) {
if (i < j) dp[i][j] = min(dp[i][j], dp[i + 1][j] + a);
if (j > i) dp[i][j] = min(dp[i][j], dp[i][j - 1] + a);
auto &oc = oo[get_pos(i, j)];
auto it = lower_bound(oc.begin(), oc.end(), i);
int cnt = 1;
for (; it != oc.end(); ++cnt) {
int jj = *it + l - 1;
dp[i][jj] = min(dp[i][jj], dp[i][j] + b + cnt * c + (jj - i + 1 - cnt * l) * a);
it = lower_bound(next(it), oc.end(), *it + l);
}
}
}
printf("%lld", dp[1][n]);
}
