#include <bits/stdc++.h>
using namespace std;
#define dbg(x) "[" #x " = " << (x) << "]"
template<typename T>
bool minimize(T& a, const T& b){
if(a > b) return a = b, true;
return false;
}
vector<int> z_function(const string& s){
int n = (int)s.size();
vector<int> z(n);
for(int i = 1, l = 0, r = 0; i < n; ++i){
z[i] = max(0, min(r - i, z[i - l]));
while(i + z[i] < n && s[i + z[i]] == s[z[i]]) ++z[i];
if(i + z[i] > r){
l = i; r = i + z[i];
}
}
return z;
}
const long long inf = 1e18;
int main(){
ios_base::sync_with_stdio(0); cin.tie(0);
#ifdef LOCAL
freopen("task.inp", "r", stdin);
freopen("task.out", "w", stdout);
#endif // LOCAL
int N; long long A, B, C;
string S;
cin >> N >> S >> A >> B >> C;
vector<vector<int>> next(N + 1, vector<int>(N + 1, N));
for(int i = N - 1; i >= 0; --i){
vector<int> z = z_function(S.substr(i, N - i));
// for(int j : z) cout << j << ' '; cout << '\n';
int mx = 0;
for(int j = i + 1; j < N; ++j){
int extend = min(j - i, z[j - i]);
while(mx < extend){
++mx;
next[i][i + mx] = j;
}
}
}
// for(int i = 0; i < N; ++i){
// for(int j = i + 1; j <= N; ++j){
// if(next[i][j] != N){
// cout << dbg(i) << dbg(j) << dbg(next[i][j]) << '\n';
// }
// }
// }
vector<vector<long long>> dp(N + 1, vector<long long>(N + 1, inf));
for(int i = 0; i < N; ++i) dp[i][i + 1] = A + B;
for(int len = 1; len <= N; ++len){
for(int i = 0, j = len; j <= N; ++i, ++j){
minimize(dp[i][j], dp[i][j - 1] + A);
minimize(dp[i][j], dp[i + 1][j] + A);
int len = j - i;
int pos = next[i][j];
int cnt_paste = 1;
while(pos < N){
// assert(pos - i - cnt_paste * len >= 0);
minimize(dp[i][pos + len], dp[i][j] + (1 + cnt_paste) * C + (pos - i - cnt_paste * len) * A + B);
pos = next[pos][pos + len];
++cnt_paste;
}
}
}
cout << dp[0][N] - B << '\n';
return 0;
}
/*
next[l][r] = minimum k that s[l...r) = s[k...k + (r - l))
dp[l][r] = minimum cost to make X = "", Y = s[l...r)
*/
