#include<bits/stdc++.h>
#pragma GCC optimize("O3,unroll-loops,fast-math")
#pragma GCC target("avx2,popcnt,bmi,bmi2,lzcnt")
#pragma GCC optimize("Ofast")
using namespace std;
#define int long long
#define in array<int, 2>
#define pb push_back
#define pob pop_back
#define INF (int)1e17
#define fast() ios_base::sync_with_stdio(false); cin.tie(NULL)
const int MX = 3e3;
const int mod1 = 1e9+7;
const int mod2 = 1e9+9;
struct Mpair
{
int v1, v2;
};
const Mpair b = {37, 31};
const Mpair ib = {621621626, 838709685};
Mpair make(int x)
{
return {x, x};
}
Mpair operator+(const Mpair& M1, const Mpair& M2)
{
Mpair ret = M1;
ret.v1+=M2.v1; (ret.v1)%=mod1;
ret.v2+=M2.v2; (ret.v2)%=mod2;
return ret;
}
Mpair operator-(const Mpair& M1, const Mpair& M2)
{
Mpair ret = M1;
ret.v1-=M2.v1; ret.v1 += mod1; (ret.v1)%=mod1;
ret.v2-=M2.v2; ret.v2 += mod2; (ret.v2)%=mod2;
return ret;
}
Mpair operator*(const Mpair& M1, const Mpair& M2)
{
Mpair ret = M1;
ret.v1*=M2.v1; (ret.v1)%=mod1;
ret.v2*=M2.v2; (ret.v2)%=mod2;
return ret;
}
in convert(Mpair m)
{
return {m.v1, m.v2};
}
Mpair ppow[MX];
Mpair ipow[MX];
void pre()
{
ppow[0] = {1, 1};
ipow[0] = {1, 1};
for(int i = 1; i < MX; i++)
{
ppow[i] = ppow[i-1]*b;
ipow[i] = ipow[i-1]*ib;
}
return;
}
signed main()
{
fast(); pre();
int n, a, b, c; cin >> n;
vector<int> St(n+1, 0);
vector<int> S(n+1, 0);
for(int i = 1; i <= n; i++)
{
char xy; cin >> xy;
St[i] = (xy - 'a' + 1);
S[n+1-i] = St[i];
}
cin >> a >> b >> c;
vector<Mpair> pref(n+1, {0,0});
for(int i = 1; i <= n; i++)
pref[i] = pref[i-1] + make(S[i])*ppow[i];
unordered_map<int, vector<int>> lst;
int forw[n+1][n+1];
int g[n+1][n+1];
for(int x = 1; x <= n; x++)
{
for(int i = 1; i <= n-x+1; i++)
{
Mpair hsh = (pref[i+x-1]-pref[i-1])*ipow[i];
if(lst[hsh.v1].empty())
lst[hsh.v1].pb(0);
forw[n+2-(i+x)][x] = lst[hsh.v1].back();
lst[hsh.v1].pb(i);
vector<int> C = lst[hsh.v1];
if((i-1) < x)
{
g[(n+2)-(i+x)][x] = n+2-x;
continue;
}
g[(n+2)-(i+x)][x] = (n+2)-(x+C[lower_bound(C.begin(), C.end(), i-x+1)-C.begin()-1]);
}
lst.clear();
}
vector<array<int, 3>> adj[n+1][n+1];
for(int x = 1; x <= n; x++)
{
for(int i = 1; i <= n+1-x; i++)
{
int pl = i; pl = g[pl][x];
int wt = 0;
while(pl <= (n+1-x))
{
wt++;
adj[i][pl+x-1].pb({i, i+x-1, (pl-i-wt*x)*a + (wt+1)*c + b});
pl = g[pl][x];
}
}
}
int dp[n+1][n+1];
for(int i = 1; i <= n; i++)
dp[i][i] = a+b;
for(int x = 2; x <= n; x++)
{
for(int i = 1; i <= (n+1-x); i++)
{
dp[i][i+x-1] = min(dp[i+1][i+x-1], dp[i][i+x-2]) + a;
for(auto [l, r, w]: adj[i][i+x-1])
dp[i][i+x-1] = min(dp[i][i+x-1], dp[l][r]+w);
}
}
cout << (dp[1][n]-b) << "\n";
return 0;
}
