#include <bits/stdc++.h>
using namespace std;
const int N = 5e3 + 5;
const int INF = 1e9;
const int K = 13;
const int NMAX = (1 << K);
int pos[N];
int pre[NMAX];
int sp[NMAX][K];
vector<int> sort_cyclic_shifts(string const& s) {
  int n = s.size();
  const int alphabet = 256;
  vector<int> p(n), c(n), cnt(max(alphabet, n), 0);
  for (int i = 0; i < n; i++) cnt[s[i]]++;
  for (int i = 1; i < alphabet; i++) cnt[i] += cnt[i - 1];
  for (int i = 0; i < n; i++) p[--cnt[s[i]]] = i;
  c[p[0]] = 0;
  int classes = 1;
  for (int i = 1; i < n; i++) {
    if (s[p[i]] != s[p[i - 1]]) classes++;
    c[p[i]] = classes - 1;
  }
  vector<int> pn(n), cn(n);
  for (int h = 0; (1 << h) < n; ++h) {
    for (int i = 0; i < n; i++) {
      pn[i] = p[i] - (1 << h);
      if (pn[i] < 0) pn[i] += n;
    }
    fill(cnt.begin(), cnt.begin() + classes, 0);
    for (int i = 0; i < n; i++) cnt[c[pn[i]]]++;
    for (int i = 1; i < classes; i++) cnt[i] += cnt[i - 1];
    for (int i = n - 1; i >= 0; i--) p[--cnt[c[pn[i]]]] = pn[i];
    cn[p[0]] = 0;
    classes = 1;
    for (int i = 1; i < n; i++) {
      pair<int, int> cur = {c[p[i]], c[(p[i] + (1 << h)) % n]};
      pair<int, int> prev = {c[p[i - 1]], c[(p[i - 1] + (1 << h)) % n]};
      if (cur != prev) ++classes;
      cn[p[i]] = classes - 1;
    }
    c.swap(cn);
  }
  return p;
}
vector<int> suffix_array_construction(string s) {
  s += "$";
  vector<int> sorted_shifts = sort_cyclic_shifts(s);
  sorted_shifts.erase(sorted_shifts.begin());
  return sorted_shifts;
}
vector<int> lcp_construction(string const& s, vector<int> const& p) {
  int n = s.size();
  vector<int> rank(n, 0);
  for (int i = 0; i < n; i++) rank[p[i]] = i;
  int k = 0;
  vector<int> lcp(n - 1, 0);
  for (int i = 0; i < n; i++) {
    if (rank[i] == n - 1) {
      k = 0;
      continue;
    }
    int j = p[rank[i] + 1];
    while (i + k < n && j + k < n && s[i + k] == s[j + k]) k++;
    lcp[rank[i]] = k;
    if (k) k--;
  }
  return lcp;
}
int get(int l, int r) {
  int k = pre[r - l + 1];
  return min(sp[l][k], sp[r - (1 << k) + 1][k]);
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n, a, b;
  cin >> n >> a >> b;
  string s;
  cin >> s;
  vector<int> suffix_array = suffix_array_construction(s);
  for (int i = 0; i < (int)suffix_array.size(); i++) {
    pos[suffix_array[i]] = i;
  }
  vector<int> LCP = lcp_construction(s, suffix_array);
  for (int i = 2; i < NMAX; i++) {
    pre[i] = pre[i >> 1] + 1;
  }
  for (int i = 0; i < n - 1; i++) {
    sp[i][0] = LCP[i];
  }
  for (int j = 1; (1 << j) <= (n - 1); j++) {
    for (int i = 0; i < n - 1; i++) {
      sp[i][j] = min(sp[i][j - 1], sp[i + (1 << (j - 1))][j - 1]);
    }
  }
  vector<int> lenz(n);
  for (int i = 0; i < n; i++) {
    int maxlen = 0;
    for (int j = i - 1; j >= 0; j--) {
      int l = pos[j], r = pos[i];
      if (l > r) swap(l, r);
      int curlen = min(i - j, get(l, r - 1));
      maxlen = max(maxlen, curlen);
    }
    lenz[i] = maxlen;
  }
  vector<int> dp(n);
  dp[0] = a;
  for (int i = 1; i < n; i++) {
    dp[i] = INF;
    for (int j = i; j >= 0; j--) {
      int cur = (j == 0 ? 0 : dp[j - 1]);
      int rem = (i - j + 1) * a;
      if (j + lenz[j] > i) rem = min(rem, b);
      dp[i] = min(dp[i], cur + rem);
    }
  }
  cout << dp[n - 1] << '\n';
  return 0;
}
