#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define int ll
#define endl '\n'
#define pb push_back
using pi = array<int, 2>;
template<class T> bool ckmin(T& a, const T& b) { return b < a ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; }
/*
x = lungimea
y = aparitii
cost_nor = A * len * ap
cost_cut = A * len + B + C * ap
A * len * ap - A * len - B - C * ap > 0
A*x*y - A*x - C*y - B > 0
y*(A*x-C) > A * x + B
y > (A * x + B) / (A * x - C)x
*/
const int INF = 1e9, BASE = 29, MOD = 1e9 + 7, N = 205;
int binpow(int a, int b) {
int res = 1;
while (b) {
if (b & 1) res = res * a % MOD;
a = a * a % MOD;
b >>= 1;
}
return res;
}
int modinv(int n) {
return binpow(n, MOD - 2);
}
int p[N], minv[N];
void precalc() {
p[0] = 1;
for (int i = 1; i < N; ++i) {
p[i] = p[i - 1] * BASE % MOD;
minv[i] = modinv(p[i]);
}
}
int n, A, B, C;
string s;
int dp[N][N];
int calc(int l, int r) {
if (r < l) return 0;
if (dp[l][r] != -1) return dp[l][r];
int m = r - l + 1;
dp[l][r] = A * m;
for (int len = max(0LL, m - (ll)sqrt(m) - 5); len <= m; ++len) {
map<int, vector<int>> ap{};
int hash = 0;
for (int i = 0; i < len; ++i) {
hash = (hash + p[i] * s[l + i] % MOD) % MOD;
}
ap[hash].pb(l);
for (int i = len; i < m; ++i) {
int j = i - len;
hash = (hash + MOD - s[l + j]) % MOD;
hash = hash * minv[1] % MOD;
hash = (hash + p[len - 1] * s[l + i] % MOD) % MOD;
int st = l + i - len + 1;
if (!ap[hash].size() || ap[hash].back() + len <= l + st) ap[hash].pb(st);
}
for (auto [h, idx] : ap) {
int curr = calc(idx[0], idx[0] + len - 1) + B + idx.size() * C;
curr += max(0LL, A * (idx[0] - l));
for (int i = 1; i < (int)idx.size(); ++i) curr += max(0LL, A * (idx[i] - (idx[i - 1] + len)));
curr += max(0LL, A * (r - (idx.back() + len) + 1));
dp[l][r] = min(dp[l][r], curr);
}
}
return dp[l][r];
}
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
precalc();
cin >> n >> s >> A >> B >> C;
bool all_a = true;
for (int i = 0; i < n; ++i) all_a &= (s[i] == 'a');
if (all_a) {
vector<int> dp(n + 1, INF);
dp[0] = 0;
for (int i = 1; i <= n; ++i) {
dp[i] = dp[i - 1] + A;
for (int len = 1; len < i; ++len) {
dp[i] = min(dp[i], dp[len] + B + C * (i / len) + A * (i % len));
}
}
cout << dp[n];
return 0;
}
for (int i = 0; i < N; ++i) {
for (int j = 0; j < N; ++j) dp[i][j] = -1;
}
cout << calc(0, n - 1) << endl;
}
