#include <bits/stdc++.h>
using namespace std;
void getZarr(string str, int Z[]);
long long search(string text, string pattern) {
  string concat = pattern + "$" + text;
  int l = concat.length();
  int Z[l];
  getZarr(concat, Z);
  long long id = pattern.length() + 1;
  long long ret = 0;
  for (long long i = id; i < l; i++) ret = max(ret, (long long)Z[i]);
  return ret;
}
void getZarr(string str, int Z[]) {
  int n = str.length();
  int L, R, k;
  L = R = 0;
  for (int i = 1; i < n; ++i) {
    if (i > R) {
      L = R = i;
      while (R < n && str[R - L] == str[R]) R++;
      Z[i] = R - L;
      R--;
    } else {
      k = i - L;
      if (Z[k] < R - i + 1)
        Z[i] = Z[k];
      else {
        L = i;
        while (R < n && str[R - L] == str[R]) R++;
        Z[i] = R - L;
        R--;
      }
    }
  }
}
long long n, a, b;
long long dp[5005];
long long ans[5005];
const long long inf = 1e16;
long long solve(long long id) {
  if (id >= n) {
    return 0;
  }
  if (dp[id] != -1) return dp[id];
  long long &ret = dp[id];
  ret = a + solve(id + 1);
  for (long long i = 1; i <= ans[id]; i++) {
    ret = min(ret, b + solve(id + i));
  }
  return ret;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  cin >> n >> a >> b;
  memset(dp, -1, sizeof dp);
  string s;
  cin >> s;
  ans[0] = 0;
  for (long long i = 1; i < n; i++) {
    long long plen = i;
    string X = s.substr(0, plen);
    string Y = s.substr(i, min(plen, n - i));
    ans[i] = search(X, Y);
  }
  cout << solve(0) << endl;
  return 0;
}
