#include <bits/stdc++.h>
using namespace std;
struct hashCode {
int n, nrHashes;
vector<int> mod;
vector<vector<int>> p, hashPref;
void init( string s, vector<int> vals, vector<int> _mod ) {
n = s.size() - 1;
nrHashes = vals.size();
mod = _mod;
p.resize( nrHashes );
for ( int h = 0; h < nrHashes; h++ ) {
p[h].resize( n + 1 );
p[h][0] = 1;
for ( int i = 1; i <= n; i++ ) {
p[h][i] = (long long)p[h][i - 1] * vals[h] % mod[h];
}
}
hashPref.resize( nrHashes );
for ( int h = 0; h < nrHashes; h++ ) {
hashPref[h].resize( n + 1 );
hashPref[h][0] = 1;
for ( int i = 1; i <= n; i++ )
hashPref[h][i] = (hashPref[h][i - 1] + (long long)p[h][i - 1] * (s[i] - 'a')) % mod[h];
}
}
vector<int> query( int l, int r ) {
vector<int> ans;
for ( int h = 0; h < nrHashes; h++ )
ans.push_back( (long long)(hashPref[h][r] - hashPref[h][l - 1] + mod[h]) % mod[h] * p[h][n - l] % mod[h] );
return ans;
}
} sir;
const int MAX_N = 2500;
long long dp[MAX_N][MAX_N];
int main() {
int n, a, b, c;
string s;
cin >> n >> s >> a >> b >> c;
s = "#" + s;
for ( int l = 1; l <= n; l++ ) {
for ( int r = l; r <= n; r++ )
dp[l][r] = (long long)a * (r - l + 1) + b;
}
int mod1 = (1e9 + 7), mod2 = (1e9 + 9);
sir.init( s, { 29, 31 }, { mod1, mod2 } );
for ( int len = 1; len <= n; len++ ) {
for ( int l = 1; l <= n - len + 1; l++ ) {
int r = l + len - 1;
dp[l - 1][r] = min( dp[l - 1][r], dp[l][r] + a );
dp[l][r + 1] = min( dp[l][r + 1], dp[l][r] + a );
long long cost = dp[l][r] + b + c;
int k = r + len;
while ( k <= n ) {
if ( sir.query( l, r ) == sir.query( k - len + 1, k ) ) {
cost += c;
dp[l][k] = min( dp[l][k], cost );
k += len;
} else {
cost += a;
k++;
}
}
}
}
cout << dp[1][n] - b << "\n";
return 0;
}
