#include<bits/stdc++.h>
using namespace std ;
typedef long long ll ;
const int MAXN = 2507 ;
const int BASE = 27 ;
ll MOD[ 2 ] = { 1000000007 , 998244353 } ;
int n ;
string a ;
ll costA , costB , costC ;
struct hsh {
int l , r ;
ll val[ 2 ] ;
void advance ( int nw ) {
for ( auto i : { 0 , 1 } ) {
val[ i ] = ( val[ i ] * BASE + nw ) % MOD[ i ] ;
}
}
};
hsh aux[ MAXN ][ MAXN ] ;
pair < int , int > nxt[ MAXN ][ MAXN ] ;
ll dp[ MAXN ][ MAXN ] ;
map < pair < ll , ll > , int > w ;
set < int > s[ MAXN ] ;
void input ( ) {
cin >> n >> a ;
cin >> costA >> costB >> costC ;
for ( int i = 1 ; i <= n ; ++ i ) {
for ( int j = i ; j <= n ; ++ j ) {
aux[ i ][ j ] = aux[ i ][ j - 1 ] ;
aux[ i ][ j ].l = i , aux[ i ][ j ].r = j ;
aux[ i ][ j ].advance ( a[ j - 1 ] - 'a' + 1 ) ;
}
}
for ( int i = 1 ; i <= n + 2 ; ++ i ) {
for ( int j = i ; j <= n + 2 ; ++ j ) {
dp[ i ][ j ] = 1e15 ;
}
}
for ( int i = 1 ; i <= n + 2 ; ++ i ) {
for ( int j = 0 ; j < i ; ++ j ) {
dp[ i ][ j ] = costB ;
}
}
for ( int len = 0 ; len < n ; ++ len ) {
w.clear ( ) ;
for ( int i = 1 ; i + len <= n ; ++ i ) {
int j = i + len ;
pair < ll , ll > hh = { aux[ i ][ j ].val[ 0 ] , aux[ i ][ j ].val[ 1 ] } ;
if ( w[ hh ] == 0 ) { w[ hh ] = i ; }
s[ w[ hh ] ].insert ( i ) ;
}
for ( int i = 1 ; i + len <= n ; ++ i ) {
int j = i + len ;
pair < ll , ll > hh = { aux[ i ][ j ].val[ 0 ] , aux[ i ][ j ].val[ 1 ] } ;
if ( w[ hh ] != i ) { continue ; }
int id = w[ hh ] ;
auto pos = s[ id ].begin ( ) ;
for ( auto x : s[ id ] ) {
while ( pos != s[ id ].end ( ) && x + len >= *pos ) {
++ pos ;
}
if ( pos != s[ id ].end ( ) ) {
nxt[ x ][ x + len ] = { *pos , *pos + len } ;
}
}
s[ id ].clear ( ) ;
}
}
}
void solve ( ) {
for ( int len = 0 ; len < n ; ++ len ) {
for ( int i = 1 ; i + len <= n ; ++ i ) {
int j = i + len ;
dp[ i ][ j ] = min ( dp[ i ][ j ] , dp[ i + 1 ][ j ] + costA ) ;
dp[ i ][ j ] = min ( dp[ i ][ j ] , dp[ i ][ j - 1 ] + costA ) ;
pair < int , int > act ;
act = { i , j } ;
int coef = 1 ;
while ( 1 ) {
act = nxt[ act.first ][ act.second ] ;
if ( act.first <= 0 ) { break ; }
++ coef ;
int lft = ( act.second - i + 1 ) - coef * ( j - i + 1 ) ;
dp[ i ][ act.second ] = min ( dp[ i ][ act.second ] , dp[ i ][ j ] + coef * costC + lft * costA + costB ) ;
}
}
}
cout << dp[ 1 ][ n ] - costB << "\n" ;
}
int main ( ) {
ios_base :: sync_with_stdio ( false ) ;
cin.tie ( NULL ) ;
int t ;
/// cin >> t ;
t = 1 ;
while ( t -- ) {
input ( ) ;
solve ( ) ;
}
return 0 ;
}
