#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define fi first
#define se second
#define for1(i,j,k) for(int i=j;i<=k;i++)
#define for2(i,j,k) for(int i=j;i>=k;i--)
#define for3(i,j,k,l) for(int i=j;i<=k;i+=l)
#define all(x) x.begin(),x.end()
#define int long long
typedef long long ll;
typedef pair<int,int> pii;
typedef double ld;
const ll maxn=2500+5;
const ll offset=2e5;
const ll inf=1e18;
const int base=350;
const ll mod=998244353;
int n,a,b,c;
string s;
int dp[maxn][maxn],lcp[maxn][maxn],nxt[maxn][maxn];
void sol()
{
cin >> n>> s>>a>>b>>c;
s='$'+s;
for1(len,1,n)
{
for2(i,n-len+1,1)
{
int j=i+len-1;
if (s[i]==s[j]) lcp[i][j]=lcp[i+1][j+1]+1;
}
}
for1(i,1,n)
{
int pos=i+1;
for1(j,i,n)
{
while (pos<=n && (lcp[i][pos] < j-i+1 || pos<=j)) pos++;
nxt[i][j]=pos;
// cerr<< i<<' '<<j<<' '<<pos<<'\n';
}
}
// return;
for1(i,0,n+1) for1(j,0,n+1) dp[i][j]=inf;
for1(len,1,n)
{
for1(i,1,n-len+1)
{
int j=i+len-1;
dp[i][j]=min(dp[i][j],len*a);
dp[i][j]=min(dp[i][j],dp[i][j-1]+a);
dp[i][j]=min(dp[i][j],dp[i+1][j]+a);
// if (i==2 && j==5) cerr<< i<<' '<<j<<' '<<dp[i][j]<<"\n";
int cur=i,cnt=1;
while(1)
{
++cnt;cur=nxt[cur][cur+len-1];
if (cur>n) break;
dp[i][cur+len-1]=min(dp[i][cur+len-1],dp[i][j]+c*cnt+b+(cur+len-1-i+1-cnt*len)*a);
// if (i==2 && cur+len-1==8) cerr<<i<<' '<<j<<" dof "<< cur+len-1-i+1-cnt*len<<' '<<dp[i][cur+len-1]<<'\n';
}
}
}
cout<< dp[1][n];
}
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
// freopen("1017G.inp","r",stdin);
// freopen("1017G.out","w",stdout);
int t=1;//cin >> t;
while (t--) {
sol();
}
}
/*
11
mississippi
10
5
2
*/
