/*input
18
aababbbababbbaabbb
1000000000
100000
10000000
*/
#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
//order_of_key #of elements less than x
// find_by_order kth element
typedef long long int ll;
#define ld long double
#define pii pair<ll,ll>
typedef tree<pii, null_type, less<pii>, rb_tree_tag, tree_order_statistics_node_update> indexed_set;
#define f first
#define s second
#define pb push_back
#define REP(i,n) for(int i=0;i<n;i++)
#define REP1(i,n) for(int i=1;i<=n;i++)
#define FILL(n,x) memset(n,x,sizeof(n))
#define ALL(_a) _a.begin(),_a.end()
#define sz(x) (int)x.size()
const ll maxn=3e3+5;
const ll maxlg=__lg(maxn)+2;
const ll INF64=4e18;
const int MOD=1e9+7;
const int INF=0x3f3f3f3f;
const ld PI=acos(-1);
const ld eps=1e-9;
#define lowb(x) x&(-x)
#define MNTO(x,y) x=min(x,(__typeof__(x))y)
#define MXTO(x,y) x=max(x,(__typeof__(x))y)
#define SORT_UNIQUE(c) (sort(c.begin(),c.end()), c.resize(distance(c.begin(),unique(c.begin(),c.end()))))
#define GET_POS(c,x) (lower_bound(c.begin(),c.end(),x)-c.begin())+1
template<typename T1,typename T2>
ostream& operator<<(ostream& out,pair<T1,T2> P){
out<<P.f<<' '<<P.s;
return out;
}
template<typename T>
ostream& operator<<(ostream& out,vector<T> V){
REP(i,sz(V)) out<<V[i]<<((i!=sz(V)-1)?" ":"");
return out;
}
ll mult(ll a,ll b){
if(a<0) a+=MOD;
return (a*b)%MOD;
}
ll mypow(ll a,ll b){
if(b<=0) return 1;
ll res=1LL;
while(b){
if(b&1) res=mult(res,a);
a=mult(a,a);
b>>=1;
}
return res;
}
ll dp[maxn][maxn];
struct node{
node* ch[26];
int idx;
};
int tot=0;
node* create(){
node* x=new node();
REP(i,26) x->ch[i]=NULL;
x->idx=(tot++);
return x;
}
node *rt=create();
int nxt[maxn][maxn];
bool ok[maxn][maxn];
vector<int> fac[maxn];
vector<pii> vv[maxn];
int32_t main(){
ios::sync_with_stdio(false),cin.tie(0);
int n;
ll A,b,c;
string s;
cin>>n>>s>>A>>b>>c;
s="0"+s;
REP1(i,n){
node *cur=rt;
for(int j=i;j<=n;j++){
if(!cur->ch[s[j]-'a']){
cur->ch[s[j]-'a']=create();
}
cur=cur->ch[s[j]-'a'];
vv[cur->idx].pb({i,j});
}
}
REP(i,tot){
int p=0;
for(auto x:vv[i]){
while(p<sz(vv[i]) and vv[i][p].f<=x.s) ++p;
if(p==sz(vv[i])) nxt[x.f][x.s]=INF;
else nxt[x.f][x.s]=vv[i][p].f;
}
}
for(int i=n;i>=1;i--){
for(int j=i;j<=n;j++) dp[i][j]=dp[i+1][j]+A;
for(int j=i;j<=n;j++){
MNTO(dp[i][j],dp[i][j-1]+A);
int len=(j-i+1);
int r=i;
int cnt=1;
while(nxt[r][r+len-1]!=INF){
r=nxt[r][r+len-1];
++cnt;
MNTO(dp[i][r+len-1],dp[i][j]+b+c*cnt+A*(r-i-(cnt-1)*len));
}
//cout<<i<<' '<<j<<' '<<dp[i][j]<<'\n';
}
}
cout<<dp[1][n];
}
