#include <bits/stdc++.h>
#define rep(i,a,b) for(int i=(a);i<=(b);++i)
#define per(i,a,b) for(int i=(a);i>=(b);--i)
#define pii pair<int,int>
#define vi vector<int>
#define fi first
#define se second
#define pb push_back
#define ALL(x) x.begin(),x.end()
#define sz(x) int(x.size())
#define ll long long
using namespace std;
const int N = 2505;
int n,lcp[N][N],nxt[N][N],A,B,C;
ll f[N][N];
char s[N];
int main(){
    cin.tie(0)->sync_with_stdio(0);
    cin >> n >> (s+1) >> A >> B >> C;
    per(i,n,1)per(j,n,1){
        if(s[i] == s[j])lcp[i][j] = lcp[i+1][j+1] + 1;
        else lcp[i][j] = 0;
    }
    rep(i,0,n)nxt[n+1][i] = n+1;
    per(i,n,1){//nxt[i][l]: the first position k >= i+l s.t. lcp[i][k] >= l
        nxt[i][0] = i;
        rep(j,1,n){
            nxt[i][j] = nxt[i][j-1];
            while(nxt[i][j] <= n && (nxt[i][j] < i + j || lcp[i][nxt[i][j]] < j))
                ++nxt[i][j];
        }
    }
    rep(len,1,n){
        rep(i,1,n-len+1){
            int j = i + len - 1;
            f[i][j] = max(f[i][j],max(f[i][j-1],f[i+1][j]));
            ll v = 1ll * A * len + B - f[i][j];//time need to put s(i,j) into clipboard
            for(int k = 1,p = i;p <= n;p = nxt[p][len],k++){
                f[i][p + len - 1] = max(f[i][p + len - 1],1ll * k * A * len - 1ll * k * C - v);
            }
        }
    }
    cout << 1ll * A * n - f[1][n] << '\n';
    return 0;
}