#include<bits/stdc++.h>
using namespace std;
#define int long long
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define isz(x) ((int)x.size())
#define sumof(x) accumulate(all(x), 0ll)
pair<int, int> mod={(int)1e9+7, (int)1e9+9};
const int base=311;
struct Hash{
pair<int, int> value;
Hash (int x=0){
value={x%mod.first, x%mod.second};
}
Hash (int x, int y){
value={x, y};
}
Hash operator-(){
return Hash((mod.first-value.first)%mod.first,
(mod.second-value.second)%mod.second);
}
Hash operator+(Hash b){
return Hash((value.first+b.value.first)%mod.first,
(value.second+b.value.second)%mod.second);
}
Hash operator*(Hash b){
return Hash(value.first*b.value.first%mod.first,
value.second*b.value.second%mod.second);
}
bool operator<(Hash b) const {
return value<b.value;
}
bool operator==(Hash b) const {
return value==b.value;
}
};
const int N=2510;
int f[N][N], add, cut, paste, n;
int g[N][N];
Hash pf[N];
Hash pw[N];
string s;
Hash get(int l, int r){
return pf[r]+(-pf[l-1])*pw[r-l+1];
}
void precalc(){
pw[0]=1;
for (int i=1; i<=n; ++i){
pw[i]=pw[i-1]*base;
}
for (int i=1; i<=n; ++i){
pf[i]=pf[i-1]*base+s[i];
}
for (int t=1; t<=n; ++t){
map<Hash, int> mp;
for (int r=t; r<=n; ++r){
Hash h1=get(r-t+1, r);
g[r][t]=mp.count(h1)?mp[h1]:-1;
if (r-t+1>=t){
Hash h2=get(r-t+1-t+1, r-t+1);
mp[h2]=r-t+1;
}
}
}
}
int count(int l, int r, int t){
if (r-l+1<t) return 0;
int pos=g[r][t];
return count(l, pos, t)+1;
}
int dp(int l, int r){
if (l>r) return 0;
if (f[l][r]!=-1) return f[l][r];
int res=dp(l, r-1)+add;
for (int t=l; t<=r; ++t){
int cnt=count(l, r, r-t+1);
if (cnt!=1) res=min(res, dp(t, r)+cut+cnt*paste+add*(r-l+1-cnt*(r-t+1)));
}
return f[l][r]=res;
}
void solve(){
memset(f, -1, sizeof f);
cin >> n >> s;
s=" "+s;
precalc();
cin >> add >> cut >> paste;
cout << dp(1, n);
}
int32_t main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int ntests=1;
// cin >> ntests;
for (int i=1; i<=ntests; ++i) solve();
return 0;
}
