#include <bits/stdc++.h>
using namespace std;
const int N = 5050;
const int M = N * N / 2;
using namespace std;
namespace SAR {
const int N = 2200000;
const int C = 22;
int wa[N], wb[N], wc[N], wd[N], sa[N], rnk[N], lcp[N], dp[N][C], pw2[C];
string r;
int n;
bool is_equal(int *r, int a, int b, int l, int n) {
  int la = r[a], lb = r[b], ra, rb;
  ra = a + l < n ? r[a + l] : -1;
  rb = b + l < n ? r[b + l] : -1;
  return (la == lb) && (ra == rb);
}
void build(string rr) {
  r = rr;
  n = r.length();
  int m = 256;
  int *x = wa, *y = wb;
  int i, j, tot, p;
  memset(wc, 0, sizeof(int) * m);
  for (i = 0; i < n; i++) wc[x[i] = r[i]]++;
  for (i = 1; i < m; i++) wc[i] += wc[i - 1];
  for (i = n - 1; i >= 0; i--) sa[--wc[x[i]]] = i;
  for (tot = 0, p = 1; tot + 1 < n; p <<= 1, m = tot + 1) {
    for (tot = 0, i = n - p; i < n; i++) y[tot++] = i;
    for (i = 0; i < n; i++)
      if (sa[i] >= p) y[tot++] = sa[i] - p;
    for (i = 0; i < n; i++) wd[i] = x[y[i]];
    memset(wc, 0, sizeof(int) * m);
    for (i = 0; i < n; i++) wc[wd[i]]++;
    for (i = 1; i < m; i++) wc[i] += wc[i - 1];
    for (i = n - 1; i >= 0; i--) sa[--wc[wd[i]]] = y[i];
    swap(x, y);
    x[sa[0]] = tot = 0;
    for (i = 1; i < n; i++)
      x[sa[i]] = is_equal(y, sa[i - 1], sa[i], p, n) ? tot : ++tot;
  }
  for (i = 0; i < n; i++) rnk[sa[i]] = i;
  for (lcp[0] = i = 0; i < n; i++)
    if (rnk[i]) {
      lcp[rnk[i]] = (i == 0) ? 0 : max(0, lcp[rnk[i - 1]] - 1);
      for (; r[i + lcp[rnk[i]]] == r[sa[rnk[i] - 1] + lcp[rnk[i]]];
           lcp[rnk[i]]++)
        ;
    }
  for (i = 1; i < n; i++) dp[i][0] = lcp[i];
  pw2[0] = 1;
  for (j = 1; j < C; j++) {
    pw2[j] = pw2[j - 1] * 2;
    for (i = 1; i + pw2[j] - 1 < n; i++)
      dp[i][j] = min(dp[i][j - 1], dp[i + pw2[j - 1]][j - 1]);
  }
}
int get_lcp(int i, int j) {
  if (i == j) return n - sa[i];
  if (i > j) swap(i, j);
  i++;
  int p = 31 - __builtin_clz(j - i + 1);
  return min(dp[i][p], dp[j - pw2[p] + 1][p]);
}
};  // namespace SAR
string s;
int dp[5500];
int main() {
  ios::sync_with_stdio(0);
  int n, a, b;
  cin >> n >> a >> b;
  cin >> s;
  SAR::build(s);
  for (int i = 1; i <= n; i++) dp[i] = i * a;
  for (int i = 0; i < n; i++) {
    dp[i + 1] = min(dp[i + 1], dp[i] + a);
    int d = 0;
    for (int j = 0; j < i; j++) {
      d = max(d, min(SAR::get_lcp(SAR::rnk[i], SAR::rnk[j]), i - j));
    }
    for (int j = 1; j <= d; j++) dp[i + j] = min(dp[i + j], dp[i] + b);
  }
  cout << dp[n] << endl;
  return 0;
}
