#include <bits/stdc++.h>
using namespace std;
const int maxn = 2505;
typedef long long ll;
int cl[maxn][maxn];
ll dp[maxn][maxn];
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
int n;
cin >> n;
string s;
cin >> s;
ll a,b,c;
cin >> a >> b >> c;
for(int len = 1;len <= n;++len)
{
for(int l = 0;l+len <= n;++l)
{
cl[len][l] = -1;
}
}
int zf[n];
int ans[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;
if(j > r)
{
l = j;
int k = j;
while(k < s.size() && s[i+k-j] == s[k])
{
k++;
}
zf[j] = k-j;
r = k-1;
}
else
{
int base = zf[i+j-l]+j-1;
if(base < r)
{
zf[j] = base-j+1;
}
else
{
l = j;
int k = r+1;
while(k < s.size() && s[i+k-j] == s[k])
{
k++;
}
zf[j] = k-j;
r =k-1;
}
}
// if(i == 2 && j == 8)
// cout << l << ' ' << r << ' ' << zf[j] << "!\n";
ans[min(zf[j],(j-i))] = min(ans[min(zf[j],(j-i))],j);
}
// cout << ans[1] << "!\n";
int cans = n+1;
for(int len = n-i;len >= 1;--len)
{
cans = min(cans,ans[len]);
//if(len == 4 && i == 2)
cl[len][i] = (cans == n+1 ? -1 : cans);
}
//cout << endl;
}
// for(int l = 0;l < n;++l)
// {
// for(int r= l;r < n;++r)
// {
// cout << cl[r-l+1][l] << ' ';
// }
// cout << endl;
// }
// cout << "!" << endl;
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]);
if(l == r)
{
dp[l][r] = a;
}
else
{
dp[l][r] = min({dp[l+1][r]+a,dp[l][r-1]+a,te + a * (r-l+1)});
}
int len = r-l+1;
int cpos = l;
ll cmin = dp[l][r] + b - a * (r-l+1) + c;
// if(l == 0 && r == 3)
// {
// cout << cmin << ' ';
// }
while(cpos != -1)
{
// if(l == 0 && r == 3)
// {
// cout << cmin << ' ' << len << ' ' << cpos << ' ' << cl[len][cpos];
// }
mn[cpos+len-1] = min(mn[cpos+len-1],cmin);
cmin += c - a*(r-l+1);
cpos = cl[len][cpos];
}
// cout << dp[l][r] << ' ';
}
// cout << "\n";
}
cout << dp[0][n-1] << "\n";
return 0;
}
