#include<bits/stdc++.h>
#define ull unsigned long long
using namespace std;
char s[2505];
long long f[2505][2505],ll[2505][2505];
ull mo=111339248186143ull,mm[2505],bs[2505];
long long dd[2505];
int hj[2505];
vector<int>g[2505];
int main(){
	int n;
	cin>>n;
	scanf("%s",s+1);
	for(int i=1;i<=n;++i)mm[i]=mm[i-1]*mo+s[i];
	bs[0]=1;
	for(int i=1;i<=n;++i)bs[i]=bs[i-1]*mo;
	int a,b,c;
	cin>>a>>b>>c;
	memset(f,63,sizeof(f));
	memset(ll,63,sizeof(ll));
	for(int i=1;i<=n;++i)f[i][i-1]=0;
	for(int l=1;l<=n;++l){
		for(int i=1;i<=n-l+1;++i){
			int j=i+l-1;
			ll[i][j]=min(ll[i][j],ll[i+1][j]+a);
			f[i][j]=min(ll[i][j],f[i][j-1]+a);
		}
		for(int i=1;i<=n;++i)g[i].clear();
		map<ull,int>mp;
		int tt=0;
		for(int i=1;i<=n-l+1;++i){
			ull xx=mm[i+l-1]-mm[i-1]*bs[l];
			int aa=mp[xx];
			if(!aa)aa=mp[xx]=++tt;
			g[aa].emplace_back(i);
		}
		for(int i=l+1;i<=n;++i){
			int dy=mp[mm[i-1]-mm[i-l-1]*bs[l]];
			int ef=lower_bound(g[dy].begin(),g[dy].end(),i)-g[dy].begin();
			if(ef<(signed)g[dy].size())hj[i]=g[dy][ef];
			else hj[i]=0;
		}
		for(int i=1;i<=n-l+1;++i){
			long long xx=f[i][i+l-1]+b+c;
			ll[i][i+l-1]=min(ll[i][i+l-1],xx);
			int kk=i+l;
			while(kk<=n-l+1){
				int wz=hj[kk];
				if(wz==0)break;
				xx+=1ll*(wz-kk)*a+c;
				ll[i][wz+l-1]=min(ll[i][wz+l-1],xx);
				kk=wz+l;
			}
		}
	}
	cout<<f[1][n]<<endl;
	return 0;
}