//Huyduocdithitp
#include <bits/stdc++.h>
typedef long long ll;
#define endl '\n'
#define yes //cout<<"YES"<<endl;
#define no //cout<<"NO"<<endl;
#define fi first
#define se second
#define pii pair<ll, ll>
#define inf 1e18
#define faster ios_base::sync_with_stdio(false);cin.tie(NULL);//cout.tie(NULL);
#define MP make_pair
#define TASK "ghuy4g"
#define start if(fopen(TASK".inp","r")){freopen(TASK".inp","r",stdin);freopen(TASK".out","w",stdout);}
#define LOG 19
#define N 2502
using namespace std;
bool ghuy4g;
const ll base = 311;
const ll mod = 1e9 + 7;
int n, A, B, C, nxt[N][N];
long long dp[2502][2502];
string s;
long long p[N], h[N];
vector<ll> vt[N][N];
unordered_map<ll, ll> mp[N];
ll cur[N];
void build() {
p[0] = 1;
h[0] = 0;
for (int i = 1; i <= n; i ++) {
h[i] = (h[i - 1] * base % mod + (s[i] - 'a')) % mod;
p[i] = p[i - 1] * base % mod;
}
}
ll get(ll l, ll r) {
return (h[r] - h[l - 1] * p[r - l + 1] % mod + mod) % mod;
}
void pre() {
//vt[0][0].push_back(0);
//ll cnt = 0;
for (int i = 1; i <= n; i ++) {
for (int j = 1; j <= n; j ++) {
dp[i][j] = inf;
}
dp[i][i] = A;
}
for (int i = 1; i <= n; i ++) {
for (int j = i; j <= n; j ++) {
ll x = get(i, j);
////cout << mp[j - i + 1][x] << endl;
//continue;
if (mp[j - i + 1][x] == 0) {
mp[j - i + 1][x] = ++ cur[j - i + 1];
}
if (j - i + 1 == 4) {
//cout << i << " " << j << " " << mp[j - i + 1][x] << endl;
}
////cout << j - i + 1 << " " << mp[j - i + 1][x] << endl;
////cout << vt[j - i + 1][mp[j - i + 1][x]].size() << endl;
//continue;
////cout << "size " << vt[4][1].size() << endl;
vt[j - i + 1][mp[j - i + 1][x]].push_back(i);
}
}
//exit(0);
for (int len = 1; len <= n; len ++) {
for (int id = 1; id <= cur[len]; id ++) {
sort(vt[len][id].begin(), vt[len][id].end());
ll it = vt[len][id].size() - 1;
//cout << len << " " << id << " " << vt[len][id].size() << " " << it << endl;
if (vt[len][id].size() == 0) continue;
//continue;
for (int j = vt[len][id].size() - 1; j >= 0; j --) {
while (it > 0 && vt[len][id][it - 1] - vt[len][id][j] >= len) {
it -- ;
}
if (it >= 0 && vt[len][id][it] - vt[len][id][j] >= len) {
nxt[len][vt[len][id][j]] = vt[len][id][it];
}
}
}
}
//cout << nxt[4][1] << endl;
//cout << nxt[3][nxt[3][1]] << endl;
}
/*
long long dp(ll i, ll j) {
if (i > j){
return 0;
}
if (i >= j) {
return A;
}
if (i < 0 || j < 0 || i > n || j > n) return inf;
long long res = min(A + dp(i + 1, j), A + dp(i, j - 1)); // mo rong
ll z = nxt[j - i + 1][i];
ll cnt = 1;
ll rc = res;
while (z) {
++ cnt;
res = min(res, B + C * cnt + dp(i, z + j - i) + A * (z + j - i - i + 1 - (j - i + 1) * cnt) );
z = nxt[j - i + 1][z];
}
return res;
}
*/
void solve() {
for (int len = 1; len <= n; len ++) {
for (int i = 1; i <= n - len + 1; i ++) {
ll j = i + len - 1;
dp[i][j] = min({dp[i][j], dp[i][j - 1] + A, dp[i + 1][j] + A}) ;
ll cnt = 1, z = nxt[j - i + 1][i];
while (z) {
++ cnt;
dp[i][z + len - 1] = min(dp[i][z + len - 1], dp[i][j] + B + C * cnt + (z + len - 1 - i + 1 - cnt * len) * A );
z = nxt[j - i + 1][z];
}
}
}
cout << dp[1][n];
}
bool klinh;
signed main(void) {
faster;
cin >> n >> s >> A >> B >> C;
s = '*' + s;
build();
pre();
solve();
cerr << fabs(&klinh - &ghuy4g) / 1048576.0;
return 0;
}
