# include <bits/stdc++.h>
using namespace std;
using ll=long long;
using Hash=pair<int,int>;
constexpr int p1=1e9+7,p2=1e9+9,Base=998244353;
int nxt[2510][2510];
ll f[2510][2510];
char s[2510];
pair<Hash,int> a[2510][2510];
Hash pw[2510],hs[2510];
inline void chkmin(ll &x,const ll &y){x=min(x,y);}
Hash operator+(const Hash &x,const Hash &y){return {(x.first+y.first)%p1,(x.second+y.second)%p2};}
Hash operator-(const Hash &x,const Hash &y){return {(x.first-y.first+p1)%p1,(x.second-y.second+p2)%p2};}
Hash operator*(const Hash &x,const Hash &y){return {(ll)x.first*y.first%p1,(ll)x.second*y.second%p2};}
inline Hash geths(int l,int r){return hs[r]-pw[r-l+1]*hs[l-1];}
int main()
{
	int n,A,B,C;
	scanf("%d%s%d%d%d",&n,s+1,&A,&B,&C);
	pw[0]={1,1};
	for(int i=1;i<=n;i++) pw[i]=pw[i-1]*Hash{Base,Base};
	for(int i=1;i<=n;i++) hs[i]=hs[i-1]*Hash{Base,Base}+Hash{s[i],s[i]};
	for(int i=1;i<=n;i++)
		for(int j=i;j<=n;j++)
			a[j-i+1][i]={geths(i,j),i};
	for(int i=1;i<=n;i++)
	{
		sort(a[i]+1,a[i]+n-i+2);
		for(int l=1,r;l<=n-i+1;l=r+1)
		{
			for(r=l;r<n-i+1 && a[i][l].first==a[i][r+1].first;r++);
			for(int j=r,k=r+1;j>=l;j--)
			{
				while(a[i][k-1].second>=a[i][j].second+i) k--;
				nxt[a[i][j].second][a[i][j].second+i-1]=(k>r?0:a[i][k].second);
			}
		}
	}
	for(int l=1;l<=n;l++)
		for(int r=l;r<=n;r++)
			f[l][r]=(ll)A*(r-l+1);
	for(int l=n;l;l--)
		for(int r=l;r<=n;r++)
		{
			if(l<r) chkmin(f[l][r],min(f[l+1][r],f[l][r-1])+A);
			for(int i=nxt[l][r],c=2,L=r-l+1;i;i=nxt[i][i+L-1],c++)
				chkmin(f[l][i+L-1],f[l][r]+(ll)A*(i+L-l-c*L)+B+(ll)C*c);
		}
	cout<<f[1][n]<<endl;
	return 0;
}