#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
typedef long long ll;
using namespace __gnu_pbds;
using namespace std;
template <typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
constexpr ll p = 31;
constexpr ll MAXN = 2510;
constexpr ll m1 = 1e9+7;
constexpr ll m2 = 1e9+9;
vector<pair<ll, ll>> powerP(MAXN, make_pair(1, 1));
pair<ll, ll> operator+(pair<ll, ll> a, pair<ll, ll> b) { return make_pair((a.first+b.first)%m1, (a.second+b.second)%m2); }
pair<ll, ll> operator-(pair<ll, ll> a, pair<ll, ll> b) { return make_pair((a.first-b.first+m1)%m1, (a.second-b.second+m2)%m2); }
pair<ll, ll> operator*(pair<ll, ll> a, pair<ll, ll> b) { return make_pair((a.first*b.first)%m1, (a.second*b.second)%m2); }
void update(pair<ll, ll> &p) {
p.first%=m1; p.first+=m1; p.first%=m1;
p.second%=m2; p.second+=m2; p.second%=m2;
}
bool operator==(pair<ll, ll> a, pair<ll, ll> b) {
update(a); update(b);
return (a.first==b.first && a.second==b.second);
}
pair<ll, ll> get_pair(ll x) {return make_pair(x, x);}
ll get_numer(char c) {return c-(int)'a' + 1;}
void genPow() {
for(int i=1; i<MAXN; ++i) {
powerP[i] = powerP[i-1]*get_pair(p);
}
}
struct HashPair {
size_t operator()(const pair<ll,ll>& p) const {
return (uint64_t(p.first) << 32) ^ p.second;
}
};
struct PolHash {
string s;
vector<pair<ll, ll>> H; // H is 1-indexed
PolHash(string s_) { // s is 0-indexed
s = s_;
int n = s.size();
H.assign(n+1, get_pair(0));
for(int i=1; i<=n; ++i) {
H[i] = get_pair(p)*H[i-1] + get_pair(get_numer(s[i-1]));
}
}
pair<ll, ll> get_hash(int a, int b) { // 0-indexed
++a; ++b;
return H[b] - H[a-1]*powerP[b-a+1];
}
bool comp(int a, int b, int c, int d) {
assert(a<=b); assert(c<=d);
assert(b<s.size()); assert(d<s.size());
if(get_hash(a,b)==get_hash(c,d)) return 1;
return 0;
}
};
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
genPow();
int n; cin >> n;
string s; cin >> s;
ll A, B, C;
cin >> A >> B >> C;
ll inf = 1e18;
PolHash phash(s);
vector<vector<ll>> dp(n,vector<ll>(n, inf));
vector<pair<pair<ll, ll>, pair<ll, ll>>> H_mapa;
for(int i=0; i<n; ++i) {
for(int j=i; j<n; ++j) H_mapa.push_back({phash.get_hash(i,j),{i,j}});
}
sort(H_mapa.begin(), H_mapa.end());
vector<vector<pair<ll, ll>>> next(n, vector<pair<ll, ll>>(n, {inf, inf}));
vector<pair<ll, ll>> b; b.push_back(H_mapa[0].second);
auto check_b = [&](vector<pair<ll, ll>> &b) {
sort(b.begin(), b.end());
int ile = b.size();
int idx = ile;
for(int i=ile-1; i>=0; --i) {
auto[x,y] = b[i];
while(idx > 0 && b[idx-1].first > b[i].second) idx--;
if(idx < ile) next[b[i].first][b[i].second] = b[idx];
}
};
for(int i=1; i<H_mapa.size(); ++i) {
if(H_mapa[i].first==H_mapa[i-1].first) {
b.push_back(H_mapa[i].second);
continue;
}
check_b(b);
while(b.size()) b.pop_back();
b.push_back(H_mapa[i].second);
}
check_b(b);
for(ll d=0; d<n; ++d) {
for(int i=0; i+d<n; ++i) {
int j = i+d;
if(i==j) {
dp[i][j] = A;
}
if(j<n-1) dp[i][j+1] = min(dp[i][j+1], dp[i][j] + A);
ll ile = 1, miedzy = 0;
pair<ll, ll> x = {i,j};
while(x.second < n) {
dp[i][x.second] = min(dp[i][x.second], dp[i][j] + B + C*ile + A*miedzy);
// if(i==2 && j==2) cout << dp[i][j] << " " << ile << " " << miedzy << " - " << x.first << " " << x.second << ", " << dp[i][j] + B + C*ile + A*miedzy << "\n";
ile++;
miedzy += next[x.first][x.second].first - x.second - 1;
x = next[x.first][x.second];
}
if(i>0) dp[i-1][j] = min(dp[i-1][j], dp[i][j] + A);
}
}
cout << dp[0][n-1] << "\n";
return 0;
}
