#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
#include <vector>
#include <unordered_map>
using namespace std;

const int N=2505;
const int P=12321;

int n;
unsigned long long h[N],p[N];
vector <int> add[N];
unordered_map <unsigned long long,int> R;
long long dp[N][N];
int nex[N][N],cnt[N];
char s[N];

int query(unsigned long long x)
{
	if(R.count(x))
		return R[x];
	return n+1;
}

unsigned long long Hash(int l,int r)
{
	return h[r]-h[l-1]*p[r-l+1];
}

int main()
{
	cin >> n;
	scanf("%s",s+1);
	long long a,b,c;
	cin >> a >> b >> c;
	for(int i=1;i<=n;i++)
		dp[i][i]=c;

	p[0]=1;
	for(int i=1;i<=n;i++)
	{
		h[i]=h[i-1]*P+s[i];
		p[i]=p[i-1]*P;
	}

	for(int len=1;len<=n;len++)
	{
		R.clear();
		for(int i=n-len+1;i>=1;i--)
		{
			int j=i+len-1;
			nex[i][j]=query(Hash(i,j));
			if(j+len-1<=n)
				R[Hash(j,j+len-1)]=j+len-1;
		}
	}

	for(int i=n;i>=1;i--)
	{
		for(int j=i;j<=n;j++)
			add[j].push_back(j-i+1);

		long long nowans=0;
		for(int j=i;j<=n;j++)
		{
			dp[i][j]=a+min(dp[i+1][j],dp[i][j-1]);
			nowans += a;
			for(auto x:add[j])
			{
				cnt[x]++, add[nex[j-x+1][j]].push_back(x);
				nowans=min(nowans,cnt[x]*c+b+dp[i][i+x-1]+(j-i+1-x*cnt[x])*a);
			}

			dp[i][j]=min(dp[i][j],nowans);
		}

		for(int i=1;i<=n;i++)
		{
			add[i].clear();
			add[i].shrink_to_fit();
			cnt[i]=0;
		}
	}

	printf("%lld\n",dp[1][n]);
	return 0;
}