#include <bits/stdc++.h>
using namespace std;
using ll = long long;
constexpr int N = 2501;
ll dp[N][N];
int nxt[N][N], z[N];
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
memset(nxt, -1, sizeof(nxt));
int n;
cin >> n;
string s;
cin >> s;
int A, B, C;
cin >> A >> B >> C;
auto z_function = [&](int i) {
memset(z, 0, sizeof(z));
int l = i, r = i;
for (int j = i + 1; j < n; ++j) {
int k = 0;
if (r > j) {
k = min(r - j, z[i + (j - l)]);
}
while (j + k < n && s[j + k] == s[i + k]) {
k += 1;
}
z[j] = k;
if (j + k > r) {
r = j + k;
l = j;
}
}
};
memset(dp, 0x3f, sizeof(dp));
for (int i = n - 1; i >= 0; --i) {
z_function(i);
int pnt = 1;
for (int j = i + 1; j < n; ++j) {
// cout << z[j] << " ";
while (pnt <= z[j] && i + pnt <= j) {
nxt[i][pnt++] = j;
}
}
// for (int len = 1; len <= n - i; ++len) {
// cout << nxt[i][len] << " ";
// }
//
// cout << endl;
if (i + 1 < n) {
for (int j = i + 1; j < n; ++j) {
dp[i][j] = dp[i + 1][j] + A;
}
}
dp[i][i] = A;
for (int j = i; j < n; ++j) {
if (j > 0) {
dp[i][j] = min(dp[i][j], dp[i][j - 1] + A);
}
int len = j - i + 1;
int x = nxt[i][len];
int cnt = 1;
while (x != -1) {
cnt += 1;
int r = x + len - 1;
dp[i][r] = min(dp[i][r], 1LL * (r - i + 1 - cnt * len) * A + dp[i][j] + B + 1LL * C * cnt);
x = nxt[x][len];
}
}
// for (int j = i; j < n; ++j) {
// cout << dp[i][j] << " ";
// }
//
// cout << endl;
}
cout << dp[0][n - 1] << '\n';
return 0;
}
