#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define all(v) begin(v), end(v)
#define pi pair<int, int>
#define vi vector<int>
using namespace std;
const int N = 2503;
const ll mod = 1e9+7, base = 311;
int n; ll a, b, c;
ll h[N], pw[N] = {1};
string s;
map<int, int> rc[N];
int nx[N][N];
ll get(int l, int r){
return (h[r] - (h[l-1] * pw[r-l+1] % mod) + mod) % mod;
}
void init(){
for(int i = 1; i <= n; i++){
h[i] = (h[i-1] * base + s[i]) % mod;
}
for(int i = 1; i < N; i++) pw[i] = (pw[i-1] * base) % mod;
for(int i = n; i >= 1; i--){
for(int j = i; j <= n; j++){
int hc = get(i, j);
if(rc[j-i].count(hc)) nx[i][j] = rc[j-i][hc];
else nx[i][j] = n+1;
}
for(int j = i; j <= n; j++){
int hc = get(j, j+j-i);
rc[j-i][hc] = j;
}
}
}
ll dp[N][N];
int main(){
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> n >> s >> a >> b >> c;
s = ' ' + s;
init();
memset(dp, 0x3f, sizeof(dp));
for(int i = 1; i <= n; i++) dp[i][i+1] = a+b;
for(int len = 1; len < n; len++){
for(int i = 1; i + len - 1 <= n; i++){
int j = i + len;
if(i > 1){
dp[i-1][j] = min(dp[i-1][j], dp[i][j] + a);
}
if(j <= n){
dp[i][j+1] = min(dp[i][j+1], dp[i][j] + a);
}
ll cur = i, cnt = 1;
while(nx[cur][cur + len-1] <= n){
if(nx[cur][cur+len-1] == 0) break;
cur = nx[cur][cur+len-1];
cnt++;
dp[i][cur + len] = min(dp[i][cur + len], dp[i][j] + c * cnt + b + a * (cur + len - i - 1ll * cnt * len));
}
}
}
// for(int i = 1; i <= n; i++){
// for(int j = 1; i + j - 1 <= n; j++){
// cout << i << " " << i+j << " ";
// cout << (dp[i][i+j] >= 1e18? -1:dp[i][i+j]) << " ";
// cout << "\n";
// }
// }
cout << dp[1][n+1] - b;
return 0;
}
