#include "bits/stdc++.h"
using namespace std;
#define mod 1000000007
#define ll long long
#define ff first
#define ss second
#define pb push_back
#define N 24
#define maxn 2510
#define INF (ll)1e18
ll n,a,b,c;
ll h[maxn],pw[maxn];
string s;
vector<ll> occ[maxn*maxn];
ll dp[maxn*maxn],pt[maxn*maxn];
ll nxt[maxn][maxn],hs[maxn][maxn];
unordered_map<ll,ll> mp;
ll get(ll i,ll j){
return hs[i][j];
}
void solve(){
cin>>n>>s>>a>>b>>c;
s='#'+s;
pw[0]=1;
for(ll i=1; i<=n; i++){
h[i]=h[i-1]*29+(s[i]-'a'+1);
pw[i]=pw[i-1]*29;
}
vector<ll> v;
for(ll i=1; i<=n; i++){
for(ll j=i; j<=n; j++){
hs[i][j]=h[j]-h[i-1]*pw[j-i+1];
v.pb(hs[i][j]);
}
}
///v.erase(unique(v.begin(), v.end()), v.end());
///sort(v.begin(), v.end());
for(ll i=0; i<v.size(); i++){
if(mp[v[i]]==0)mp[v[i]]=i+1;
}
for(ll i=1; i<=n; i++){
for(ll j=i; j<=n; j++)hs[i][j]=mp[hs[i][j]];
}
for(ll i=n; i>0; i--){
////cout << "------------" << endl;
for(ll j=i; j<=n; j++){
ll cur=hs[i][j];
occ[cur].pb(i);
/**cout << "hash " << i << " " << p << endl;
cout << "occurrences: ";
for (int ds : occ[cur_hs])
cout << ds << " ";
cout << endl;*/
if(occ[cur].size()==1){
dp[cur]=dp[hs[i+1][j]]+a;
nxt[j-i+1][j]=n+1;
pt[cur]=-1;
}
else{
dp[cur]=min(dp[cur],dp[hs[i+1][j]]+a);
if(pt[cur]==-1)pt[cur]++;
while(occ[cur][pt[cur]]>j)pt[cur]++;
pt[cur]--;
///cout << i << endl;
if(pt[cur]==-1)nxt[j-i+1][j]=n+1;
else nxt[j-i+1][j]=occ[cur][pt[cur]]+(j-i);
///cout << "step " << i << " " << p << " " << nxt[p - i + 1][p] << endl;
}
}
for(ll j=i; j<=n; j++){
ll cur=get(i,j),len=j-i+1;
ll cost=dp[cur]+b+c;
if(occ[get(i,j)].size()<2)break;
ll pos=j,pp=(ll)occ[cur].size()-1;
///dp[get_hash(i, k)] = min(dp[get_hash(i, k)], cos);
//cout << "-------------------" << endl;
///cout << i << " " << k << endl;
while(pos<=n){
//cout << pos << " " << cost << endl;
ll to=nxt[len][pos];
if(to>n)break;
cost=cost+(to-pos-len)*a;
cost=cost+c;
///cout << "stop " << occ[clip_hash][pt] << endl;
///cost = cost + (occ[clip_hash][pt] - pos) * a;
///cost = cost + c;
pos=to;
dp[hs[i][pos]]=min(dp[hs[i][pos]],cost);
/**int to = pos + clip_len - 1;
if (to > n)
{
break;
}
if (get_hash(pos, to) == clip_hash)
{
cost = cost + c;
pos = pos + clip_len;
hs_dp[get_hash(i, to)] = min(hs_dp[get_hash(i, to)], cost);
}
else
{
pos ++;
cost += a;
}*/
}
}
for(ll j=i; j<=n; j++){
dp[hs[i][j]]=min(dp[hs[i][j]],dp[hs[i][j-1]]+a);
}
}
/**for (int i = 1; i <= n; i ++, cout << endl)
for (int j = i; j <= n; j ++)
cout << hs_dp[get_hash(i, j)] << " ";*/
cout<<dp[hs[1][n]]<<'\n';
}
int main(){
// freopen("in.txt","w",stdout);
// freopen("out.txt","r",stdin);
ios_base::sync_with_stdio(0); cin.tie(0);
ll t=1;
// cin>>t;
while(t--) solve();
}
