#pragma GCC optimize("Ofast,unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pll pair<long long, long long>
#define pb push_back
#define F first
#define S second
#define all(x) (x).begin(), (x).end()
const ll N = 3000;
const ll inf = 1e18;
const ll mod = 1e9 + 7;
const ll block = 350;
ll n,a,b,c;
string s;
vector<ll> z_function(string s) {
ll n = s.length();
vector<ll> z(n);
ll l = 0, r = 0;
for (int i = 0; i < n; ++i) {
if (i <= r) z[i] = min(r - i * 1ll + 1, z[i - l]);
while (i + z[i] < n && s[z[i]] == s[i + z[i]]) ++z[i];
if (i + z[i] - 1 > r) {
l = i;
r = i + z[i] - 1;
}
}
return z;
}
struct ccjv{ll l,r,cnt;};
ll st[N][13], dp[N][N];
vector<ccjv>adj[N][N];
ll get(ll l, ll r){
ll p = 31 - __builtin_clz(r - l + 1);
return max(st[l][p], st[r - (1 << p) + 1][p]);
}
void to_thic_cau(){
cin >> n >> s >> a >> b >> c;
s = " " + s;
for(ll i = 1; i <= n;i++){
for(ll j = 1; j <= n;j++) dp[i][j] = (j - i + 1) * a;
}
for(int i = 1; i <= n;i++){
string t;
for(int j = i; j <= n;j++) t += s[j];
vector<ll>z = z_function(t);
ll sz = (ll)t.size() - 1;
for(int i = 0; i <= sz;i++) st[i][0] = z[i];
for(int j = 1; j <= 12;j++){
for(int i = 0; i + (1 << j) <= sz + 1;i++) st[i][j] = max(st[i][j-1], st[i + (1 << (j - 1))][j - 1]);
}
for(int len = 1; len <= sz;len++){
ll cnt = 0, idx = -1, fir = -1;
while(1){
ll l = idx + 1, r = sz, pos = -1;
while(l <= r){
ll mid = (l + r) / 2;
if(get(idx + 1, mid) >= len) pos = mid, r = mid - 1;
else l = mid + 1;
}
if(pos == -1) break;
if(fir == -1) fir = pos;
idx = pos + len - 1, cnt++;
adj[fir + i][idx + i].pb({fir + i, fir + len - 1 + i, cnt});
}
}
}
for(int len = 0; len <= n;len++){
for(ll i = 1; i + len <= n;i++){
ll j = i + len;
for(auto x : adj[i][j]){
ll l = x.l, r = x.r, cnt = x.cnt;
if(l == i && r == j) continue;
dp[i][j] = min(dp[i][j], ((j - i + 1) - (r - l + 1) * cnt) * a + b + dp[l][r] + c * cnt);
}
if(i - 1 >= 0) dp[i-1][j] = min(dp[i-1][j], dp[i][j] + a);
if(j + 1 <= n) dp[i][j+1] = min(dp[i][j+1], dp[i][j] + a);
}
}
cout << dp[1][n] << "\n";
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
ll tc = 1;
//cin >> tc;
while(tc--) to_thic_cau();
}
