/* Im the best and i work like that */
#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair < int, int > pii;
typedef pair < ll, ll > pll;
#define F first
#define S second
#define all(x) x.begin(),x.end()
#define Mp make_pair
#define point complex
#define endl '\n'
#define SZ(x) (int)x.size()
#define fast_io ios::sync_with_stdio(0), cin.tie(0), cout.tie(0)
#define file_io freopen("input.txt", "r+", stdin); freopen("output.txt", "w+", stdout);
#define mashtali return cout << "Hello, World!", 0;
#define int ll
const int N = 2510;
const int LOG = 20;
const ll inf = 8e18;
const double pi = acos(-1);
const ld eps = 1e-18;
const ld one = 1.;
const ll mod = 16227933338363;
const ll base = 1e3 + 9;
ll pw(ll a, ll b, ll M, ll ret = 1) { if(a == 0) return 0; a %= M; while(b) { ret = (b & 1? ret * a % M : ret), a = a * a % M, b >>= 1; } return ret % M; }
mt19937 rng(time(nullptr));
int n, par[N];
ll A, B, C, Hsh[N][N], P[N], dp[N][N]; /// dp -> how much we can save
string s;
inline ll get(int l, int r)
{
return Hsh[l][r];
}
int32_t main()
{
fast_io;
cin >> n >> s >> A >> B >> C;
s = "." + s;
for(int i = 1; i <= n; i ++)
{
for(int j = i; j <= n; j ++)
{
Hsh[i][j] = (Hsh[i][j - 1] * base + s[j]) % mod;
}
}
for(int len = 1; len <= n; len ++)
{
memset(par, -1, sizeof par);
vector < pll > vec;
for(int i = len; i <= n; i ++)
{
vec.push_back(Mp(get(i - len + 1, i), i));
}
for(int i = 1; i <= n; i ++)
{
dp[i][i + len - 1] = max({dp[i][i + len - 1], dp[i + 1][i + len - 1], dp[i][i + len - 2]});
}
sort(all(vec));
for(int i = len; i <= n; i ++)
{
ll cu = get(i - len + 1, i);
int id = lower_bound(all(vec), Mp(cu, 1ll * i + len)) - vec.begin();
if(id < SZ(vec) && vec[id].F == cu)
{
par[i] = vec[id].S;
}
}
for(int i = len; i <= n; i ++)
{
int nxt = par[i], cnt = 1;
ll cu = dp[i - len + 1][i];
while(nxt != -1)
{
cnt ++;
dp[i - len + 1][nxt] = max(dp[i - len + 1][nxt], cu + 1ll * len * (cnt - 1) * A - B - 1ll * cnt * C);
nxt = par[nxt];
}
}
}
cout << 1ll * n * A - dp[1][n];
return 0;
}
/* check corner case(n = 1?), watch for negetive index or overflow */
