#include <bits/stdc++.h>
using namespace std;
const int tests = 0;
#define f first
#define s second
typedef long long ll;
typedef pair<ll,ll> pi;
const ll mod1 = 1e9+7;
const ll mod2 = 1e9+9;
ll mult = 29;
ll binexp1(ll num, ll p){
if(p == 0) return 1;
if(p == 1) return num;
ll ans = binexp1(num, p/2LL);
ans = ans*ans%mod1;
if(p&1) ans = ans*num%mod1;
return ans;
}
ll binexp2(ll num, ll p){
if(p == 0) return 1;
if(p == 1) return num;
ll ans = binexp2(num, p/2LL);
ans = ans*ans%mod2;
if(p&1) ans = ans*num%mod2;
return ans;
}
struct hashnum{
int sz = 0;
ll num = 0;
ll num1 = 0, num2 = 0;
void add(char a){
num1 *= mult; num1 += (a-'a'+1);
num1 %= mod1;
num2 *= mult; num2 += (a-'a'+1);
num2 %= mod2;
sz++;
num = num2*mod2 + num1;
}
void rem(char a){
num1 -= binexp1(mult, sz-1)*(ll)(a-'a'+1);
num1 %= mod1;
if(num1 < 0) num1 += mod1;
num2 -= binexp2(mult, sz-1)*(ll)(a-'a'+1);
num2 %= mod2;
if(num2 < 0) num2 += mod2;
sz--;
num = num2*mod2 + num1;
}
};
void solve(){
int n; cin >> n;
string s; cin >> s;
ll a,b,c; cin >> a >> b >> c;
ll dp[n+1][n+1];
//set up array
for(int i = 1; i <= n; i++){
for(int j = 1; j+i-1 <= n; j++){
dp[i][j] = a*(ll)(i);
}
}
//do dp
for(int sz = 1; sz <= n; sz++){
hashnum curhash;
vector<int> next(n+1, n+1);
vector<ll> shash(n+1);
map<ll, int> last;
for(int i = 1; i <= sz; i++) curhash.add(s[i-1]);
for(int l = 1; l+sz-1 <= n; l++){
if(sz != 1){
dp[sz][l] = min(dp[sz][l], a+min(dp[sz-1][l], dp[sz-1][l+1]));
}
//go through
if(l > 1){
curhash.rem(s[l-2]);
curhash.add(s[l+sz-2]);
}
//assign this substring hash
shash[l] = curhash.num;
//add the newly valid hash to the map
if(l-sz > 0){
last[shash[l-sz]] = l-sz;
}
auto it = last.find(shash[l]);
if(it != last.end()){
next[it->s] = l;
}
}
for(int l = 1; l <= n; l++){
int r = next[l];
for(ll i = 2; r <= n; i++){
//cost = letter cost + pastes + cut + creation - extra letter count
dp[r-l+sz][l] = min(dp[r-l+sz][l], a*(ll)(r-l - (i-1)*sz) + c*i + b + dp[sz][l]);
r = next[r];
}
}
}
cout << dp[n][1] << "\n";
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0);
int t = 1;
if(tests) cin >> t;
while(t--) solve();
}
