#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx,popcnt,sse4,abm")
#include<bits/stdc++.h>
#define int long long
#define quick ios::sync_with_stdio(0);cin.tie(0);
#define rep(x,a,b) for(int x=a;x<=b;x++)
#define repd(x,a,b) for(int x=a;x>=b;x--)
#define lowbit(x) (x&-x)
#define sz(x) (int)(x.size())
#define F first
#define S second
#define all(x) x.begin(),x.end()
#define mp make_pair
#define eb emplace_back
using namespace std;
typedef pair<int,int> pii;
void debug(){
cout<<"\n";
}
template <class T,class ... U >
void debug(T a, U ... b){
cout<<a<<" ",debug(b...);
}
const int N=25e2+7;
const int INF=1e18;
const int p=29;
const int Mod=462'779'347'772'851;
int pref[N][N];
int dp[N][N];
string s;
const int M=1e7;
vector<int> v[M];
void build(int n){
rep(i,1,n){
rep(j,i,n){
pref[i][j]=pref[i][j-1]*p%Mod+s[j-1]-'a'+2;
if(pref[i][j]>=Mod) pref[i][j]-=Mod;
}
}
}
int nxt[N];
bool vis[M];
signed main(){
quick
int n;
cin>>n;
cin>>s;
double St=clock();
build(n);
int a,b,c;
cin>>a>>b>>c;
map<int,int > mx;
int cnt=1;
rep(i,1,n){
rep(j,i,n){
dp[i][j]=(j-i+1)*a;
if(!mx[pref[i][j]]) mx[pref[i][j]]=cnt++;
v[mx[pref[i][j]]].eb(i);
}
}
rep(L,1,n){
fill(nxt,nxt+n+1,-1);
rep(l,1,n-L+1){
int r=l+L-1;
int qx=mx[pref[l][r]];
int n2=sz(v[qx]);
if(l<r) dp[l][r]=min({dp[l][r],dp[l][r-1]+a,dp[l+1][r]+a});
if(!vis[qx]&&n2!=1){
int _r=0;
int n2=sz(v[qx]);
rep(i,0,n2-1){
while(_r<n2&&v[qx][_r]<=v[qx][i]+L-1) _r++;
nxt[v[qx][i]]=(_r>=n2 ? -1 : v[qx][_r]);
if((clock()-St)/CLOCKS_PER_SEC>=2.95) break;
}
vis[qx]=true;
}
int px=nxt[l];
int pst=1;
while(px!=-1){
dp[l][px+L-1]=min(dp[l][px+L-1],(px-l-pst*L)*a+pst*c+b+c+dp[l][r]);
pst++;
px=nxt[px];
if((clock()-St)/CLOCKS_PER_SEC>=2.95) break;
}
if((clock()-St)/CLOCKS_PER_SEC>=2.95) break;
}
if((clock()-St)/CLOCKS_PER_SEC>=2.95) break;
}
cout<<dp[1][n]<<"\n";
return 0;
}
