#include <bits/stdc++.h>
using namespace std;
const int maxn = 2505;
typedef long long ll;
int cl[maxn][maxn],zf[maxn],ans[maxn];
ll dp[maxn][maxn];
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
ll n,a,b,c;
string s;
cin >> n >> s >> a >> b >> c;
for(int len = 1;len <= n+1;++len)
for(int l = 0;l+len <= n+1;++l)
cl[len][l] = n+1;
for(int i = n-1;i >= 0;--i)
{
zf[i] = 0;
int l = i,r = i;
ans[1] = n+1;
for(int j = i+1;j < n;++j)
{
ans[j-i+1] = n+1;
zf[j] = 0;
if(j <= r)
zf[j] = min(r-j+1,zf[j-l+i]+j);
while(j+zf[j] < n && s[j+zf[j]] == s[i+zf[j]])
zf[j]++;
ans[min(zf[j],(j-i))] = min(ans[min(zf[j],(j-i))],j);
}
for(int len = n-i;len >= 1;--len)
cl[len][i] = min(ans[len],cl[len+1][i]);
}
for(int l = n-1;l >= 0;--l)
{
vector<ll> mn(n,0);
ll te = 0;
for(int r = l;r < n;++r)
{
te = min(te,mn[r]);
dp[l][r] = (l==r ? a : min({dp[l+1][r]+a,dp[l][r-1]+a,te + a * (r-l+1)}));
int len = r-l+1,cpos = l;
ll cmin = dp[l][r] + b - a * len + c;
while(cpos != n+1)
{
mn[cpos+len-1] = min(mn[cpos+len-1],cmin);
cmin += c - a*len;
cpos = cl[len][cpos];
}
}
}
cout << dp[0][n-1] << "\n";
}
