#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
//#include "temp.cpp"
#include <cstdio>
using namespace std;
#ifndef ONLINE_JUDGE
#define dbg(x) cerr << #x <<" "; print(x); cerr << endl;
#else
#define dbg(x)
#endif
#define sz(x) (int((x).size()))
#define len(x) (int)x.length()
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define clr(x) (x).clear()
#define uniq(x) x.resize(unique(all(x)) - x.begin());
#define blt(x) __builtin_popcount(x)
#define pb push_back
#define popf pop_front
#define popb pop_back
void print(long long t) {cerr << t;}
void print(int t) {cerr << t;}
void print(string t) {cerr << t;}
void print(char t) {cerr << t;}
void print(double t) {cerr << t;}
void print(long double t) {cerr << t;}
void print(unsigned long long t) {cerr << t;}
template <class T, class V> void print(pair <T, V> p);
template <class T> void print(vector <T> v);
template <class T> void print(set <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T> void print(multiset <T> v);
template <class T, class V> void print(T v[],V n) {cerr << "["; for(int i = 0; i < n; i++) {print(v[i]); cerr << " "; } cerr << "]";}
template <class T, class V> void print(pair <T, V> p) {cerr << "{"; print(p.first); cerr << ","; print(p.second); cerr << "}";}
template <class T> void print(vector <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(deque <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(set <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(multiset <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T, class V> void print(map <T, V> v) {cerr << "[ "; for (auto i : v) {print(i); cerr << " ";} cerr << "]";}
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
#define nl '\n'
// for grid problems
int dx[8] = {-1,0,1,0,1,-1,1,-1};
int dy[8] = {0,1,0,-1,1,1,-1,-1};
// lowest / (1 << 17) >= 1e5 / (1 << 18) >= 2e5 / (1 << 21) >= 1e6
void fastIO() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr); cout.tie(nullptr);
}
// file in/out
void setIO(string str = "") {
fastIO();
if (str != "") {
freopen((str + ".in").c_str(), "r", stdin);
freopen((str + ".out").c_str(), "w", stdout);
}
}
// Indexed Set
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
const int N = 2605;
const long long inf = 1e15;
long long a, b, c, dp[N][N], nxt[N];
int n;
string s;
const long long mod = 1e9 + 7;
long long h1[N], h2[N];
long long pw1[N], pw2[N];
long long compute1(int l, int r) {
return (h1[l] - (pw1[r - l + 1] * h1[r + 1]) % mod + mod) % mod;
}
long long compute2(int l, int r) {
return (h2[l] - (pw2[r - l + 1] * h2[r + 1]) % mod + mod) % mod;
}
pair<long long, long long> add(int l, int r) {
l--, r--;
pair<long long, long long> par;
par.first = compute1(l, r);
par.second = compute2(l, r);
return par;
}
struct hash_pair {
template <class T1, class T2>
size_t operator()(const pair<T1, T2>& p) const
{
auto hash1 = hash<T1>{}(p.first);
auto hash2 = hash<T2>{}(p.second);
if (hash1 != hash2) {
return hash1 ^ hash2;
}
// If hash1 == hash2, their XOR is zero.
return hash1;
}
};
unordered_map<pair<long long, long long>, vector<int>, hash_pair> mp;
void solve_() {
cin >> n >> s;
cin >> a >> b >> c;
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= n; j++) {
dp[i][j] = inf;
}
}
mp.reserve((N * N) / 2);
//
for(int i = n - 1; i >= 0; i--) {
h1[i] = ((h1[i + 1] * 37ll) % mod + s[i] - 'a' + 1) % mod;
h2[i] = ((h2[i + 1] * 29ll) % mod + s[i] - 'a' + 1) % mod;
}
pw1[0] = pw2[0] = 1;
for(int i = 1; i <= n; i++) {
pw1[i] = (pw1[i - 1] * 37ll) % mod;
pw2[i] = (pw2[i - 1] * 29ll) % mod;
}
for(int len = 1; len <= n; len++) {
for(int l = 1; l + len - 1 <= n; l++) {
int r = l + len - 1;
nxt[l] = n + 1;
mp[add(l, r)].push_back(l);
if(len == 1) {
dp[l][r] = a;
} else {
dp[l][r] = min(dp[l][r], dp[l][r - 1] + a);
dp[l][r] = min(dp[l][r], dp[l + 1][r] + a);
}
}
for(int l = n - len + 1; l >= 1; l--) {
int r = l + len - 1;
auto pr = add(l, r);
auto it = lower_bound(all(mp[pr]), r + 1);
if(it != mp[pr].end()) {
nxt[l] = *it;
}
int li = l;
long long pp = dp[l][r], cnt = 1;
while(r <= n) {
dp[l][r] = min(dp[l][r], pp + cnt * c + b + (r - l + 1 - cnt * len) * a);
li = nxt[li];
r = li + len - 1;
cnt++;
}
}
for(int l = 1; l + len - 1 <= n; l++) {
int r = l + len - 1;
mp[add(l, r)].clear();
}
}
assert(dp[1][n] >= 0);
cout << dp[1][n] << '\n';
}
int main() {
setIO();
auto solve = [&](int test_case)-> void {
while(test_case--) {
solve_();
}
};
int test_cases = 1;
// cin >> test_cases;
solve(test_cases);
return 0;
}
