#include <bits/stdc++.h>
using namespace std;
const int N = 2500 + 10;
int n;
string s;
int A, B, C;
using ull = unsigned long long;
const ull base = 19937;
ull h[N], pw[N];
inline ull getHash(int l, int r) { return h[r] - h[l - 1] * pw[r - l + 1]; }
vector<int> pos[N];
int nxt[N];
long long f[N][N];
int32_t main() {
cin.tie(0)->sync_with_stdio(0);
cin >> n;
cin >> s;
cin >> A >> B >> C;
s = '@' + s;
{ // init hash
pw[0] = 1;
for (int i = 1; i <= n; ++i) {
h[i] = h[i - 1] * base + s[i];
pw[i] = pw[i - 1] * base;
}
}
memset(f, 14, sizeof f);
for (int i = 1; i <= n; ++i) f[i][i] = A;
for (int len = 1; len <= n; ++len) {
vector<ull> allH;
for (int i = 1; i <= n - len + 1; ++i) allH.push_back(getHash(i, i + len - 1));
sort(allH.begin(), allH.end());
allH.erase(unique(allH.begin(), allH.end()), allH.end());
for (int i = 1; i <= n - len + 1; ++i) {
int it = upper_bound(allH.begin(), allH.end(), getHash(i, i + len - 1)) - allH.begin();
pos[it].push_back(i);
}
fill(nxt + 1, nxt + n + 1, 0);
for (int idx = 1; idx <= (int)allH.size(); ++idx) {
for (int i = 0, it = 0; i < (int)pos[idx].size(); ++i) {
for (; pos[idx][it] + len - 1 < pos[idx][i]; ++it) nxt[pos[idx][it]] = pos[idx][i];
}
pos[idx].clear();
}
for (int l = n - len + 1; l >= 1; --l) {
const int r = l + len - 1;
{ // cur
auto& ret = f[l][r];
ret = min({ret, f[l + 1][r] + A, f[l][r - 1] + A});
}
{ // update
long long updCost = f[l][r] + B + C;
for (int j = nxt[l], last = l; j; last = j, j = nxt[j]) {
updCost += 1ll * (j - last - len) * A + C;
auto& ret = f[l][j + len - 1];
ret = min(ret, updCost);
}
}
}
}
cout << f[1][n] << "\n";
}
