#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 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<vector<ll>>> dp(n,vector<vector<ll>>(n, vector<ll>(2,inf)));
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][0] = A;
dp[i][j][1] = A + B;
}
dp[i][j][0] = min(dp[i][j][0], dp[i][j][1] + C);
if(j<n-1) dp[i][j+1][0] = min(dp[i][j+1][0], dp[i][j][0] + A);
ll ile = 1;
for(int x=j+1; x+d<n; x+=d+1) {
++ile;
if(phash.comp(i,j,x,x+d)) {
dp[i][x+d][0] = min(dp[i][x+d][0], dp[i][j][0] + B + C*ile);
dp[i][x+d][1] = min(dp[i][x+d][1], dp[i][j][0] + B + C*ile - C);
} else break;
}
dp[i][j][1] = min(dp[i][j][1], dp[i][j][0] + B);
if(i>0) dp[i-1][j][1] = min(dp[i-1][j][1], dp[i][j][1] + A);
dp[i][j][0] = min(dp[i][j][0], dp[i][j][1] + C);
}
}
cout << dp[0][n-1][0] << "\n";
return 0;
}
