//Challenge: Accepted
#include <bits/stdc++.h>
using namespace std;
#ifdef zisk
void debug(){cout << endl;}
template<class T, class ... U> void debug(T a, U ... b){cout << a << " ", debug(b...);}
template<class T> void pary(T l, T r) {
while (l != r) cout << *l << " ", l++;
cout << endl;
}
#else
#define debug(...) 0
#define pary(...) 0
#endif
#define ll long long
#define maxn 2505
#define pii pair<int, int>
#define ff first
#define ss second
#define io ios_base::sync_with_stdio(0);cin.tie(0);
const ll inf = 1LL<<60;
int nxt[maxn][maxn];
ll dp[maxn][maxn], g[maxn][maxn];
int main() {
io
int n;
cin >> n;
string s;
cin >> s;
ll A, B, C;
cin >> A >> B >> C;
for (int i = 0;i < n;i++) {
for (int j = 0;j < n;j++) {
dp[i][j] = inf, nxt[i][j] = 1<<30;
g[i][j] = inf;
}
}
for (int i = 0;i < n;i++) {
string t = s.substr(i, n - i);
int siz = n - i;
vector<int> z(siz, 0), fi(siz, 1<<30);
int lef = 0, rig = 0;
for (int j = 1;j < siz;j++) {
if (j > rig) lef = j, rig = j;
else z[j] = min(z[j - lef], rig - j + 1);
while (j + z[j] < siz && t[j + z[j]] == t[z[j]]) z[j]++;
int v = min(j, z[j]);
fi[v] = min(fi[v], j);
if (j + z[j] - 1 > rig) lef = j, rig = j + z[j] - 1;
}
for (int j = siz - 2;j >= 0;j--) fi[j] = min(fi[j], fi[j+1]);
for (int j = 1;j < siz;j++) {
nxt[i][j-1] = i + fi[j];
if (nxt[i][j-1] < n) debug(i, j-1, i + fi[j]);
}
}
for (int x = 0;x < n;x++) {
for (int i = 0;i < n - x;i++) {
int j = i + x;
dp[i][j] = min(dp[i][j], A * (x + 1) + B);
g[i][j] = min(g[i][j], dp[i][j] + C + B);
if (i) {
dp[i-1][j] = min(dp[i-1][j], g[i][j] + A);
g[i-1][j] = min(g[i-1][j], g[i][j] + A);
}
if (j < n - 1) dp[i][j+1] = min(dp[i][j+1], dp[i][j] + A);
int cur = nxt[i][x], cnt = 2;
//debug(i, j);
while (cur < n) {
//debug("to", cur, cur + x, dp[i][j] + C * (cnt) + (cur + x - i + 1 - ((x+1) * cnt)) * A + B);
dp[i][cur + x] = min(dp[i][cur + x], dp[i][j] + C * (cnt) + (cur + x - i + 1 - ((x+1) * cnt)) * A + B);
g[i][cur + x] = min(g[i][cur + x], dp[i][cur + x]);
cur = nxt[cur][x];
cnt++;
}
//debug(i, j, dp[i][j]);
}
//debug();
}
cout << dp[0][n-1] - B << endl;
}
