#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
#include <bits/stdc++.h>
using namespace std;
using ll = long long; using pii = pair<ll,ll>;
const ll Nm = 2505; const ll INF = 1e18;
const ll a1 = 123456789; const ll p1 = ((ll)1e9+7);
ll s1[Nm+1];
ll expa1[Nm+1];
ll hsh1[Nm+1];
ll N; string s;
ll A,B,C;
gp_hash_table<ll,ll> dp[Nm+1]; //dp[len][hsh] -> val
map<pii,vector<ll>> locs; //{len,hsh} -> vector of positions
int main() {
ios_base::sync_with_stdio(false); cin.tie(0);
cin >> N >> s >> A >> B >> C;
expa1[0]=1;
hsh1[0]=0;
for (ll i=0;i<Nm;i++) {
expa1[i+1]=(a1*expa1[i])%p1;
s1[i]=s[i]-'a'+1;
hsh1[i+1]=(a1*hsh1[i]+s[i]-'a'+1)%p1;
}
for (ll i=0;i<N;i++) {
for (ll j=(i+1);j<=N;j++) {
ll hv = hsh1[j]-expa1[j-i]*hsh1[i];
hv = (hv + p1*(2-hv/p1))%p1;
dp[j-i][hv]=INF;
locs[{j-i,hv}].push_back(i);
}
}
dp[0][0]=0;
for (ll L=1;L<=N;L++) {
for (ll i=0;i<=(N-L);i++) {
ll hv0 = hsh1[i+L-1]-expa1[L-1]*hsh1[i];
hv0 = (hv0 + p1*(2-hv0/p1))%p1;
ll hv1 = (a1*hv0 + s1[i+L-1])%p1;
ll hv2 = hsh1[i+L]-expa1[L-1]*hsh1[i+1];
hv2 = (hv2 + p1*(2-hv2/p1))%p1;
dp[L][hv1] = min(dp[L][hv1],A+dp[L-1][hv0]);
dp[L][hv1] = min(dp[L][hv1],A+dp[L-1][hv2]);
}
for (pii p0: dp[L]) {
ll hsh = p0.first; ll dpv = p0.second;
if (locs[{L,hsh}].size()==1) {continue;}
vector<ll> vlc = locs[{L,hsh}];
sort(vlc.begin(),vlc.end());
for (ll x: vlc) {
ll y = x;
ll njp = 0;
while(1) {
auto A0 = lower_bound(vlc.begin(),vlc.end(),y);
if (A0==vlc.end()) {
break;
} else {
njp++;
y = (*A0)+L;
//string chars in range [x,y)
ll hv0 = hsh1[y]-hsh1[x]*expa1[y-x];
hv0 = (hv0+p1*(2-hv0/p1))%p1;
dp[y-x][hv0]=min(dp[y-x][hv0],A*(y-x-njp*L)+B+dpv+C*njp);
}
}
}
}
}
cout << dp[N][hsh1[N]] <<"\n";
}
//for a stored sub-block S0 (length x):
//x starting positions
//if O-tilde(#(occurrences of S0)^2):
//sum over x=x0: O(N^2) worst case -> bad.
//wait no: should (???) amortize to O(N^2logN)???
//ok imma code it
