#include <bits/stdc++.h>
using namespace std;
char s[5005], t[5005];
int n, a, b;
int dp[5005];
int sa[5005], rnk[5005], lcp[5005], cnt[5005];
void build(char *s) {
  int n = strlen(s) + 1, m = 256;
  int *x = rnk, *y = lcp, *z;
  for (int i = 0; i < m; i++) cnt[i] = 0;
  for (int i = 0; i < n; i++) cnt[x[i] = s[i]]++;
  for (int i = 1; i < m; i++) cnt[i] += cnt[i - 1];
  for (int i = n - 1; i >= 0; i--) sa[--cnt[x[i]]] = i;
  for (int j = 1, p = 1; p < n; j <<= 1, m = p) {
    p = 0;
    for (int i = n - j; i < n; i++) y[p++] = i;
    for (int i = 0; i < n; i++)
      if (sa[i] >= j) y[p++] = sa[i] - j;
    for (int i = 0; i < m; i++) cnt[i] = 0;
    for (int i = 0; i < n; i++) cnt[x[i]]++;
    for (int i = 1; i < m; i++) cnt[i] += cnt[i - 1];
    for (int i = n - 1; i >= 0; i--) sa[--cnt[x[y[i]]]] = y[i];
    z = x, x = y, y = z;
    x[sa[0]] = 0, p = 1;
    for (int i = 1; i < n; i++) {
      x[sa[i]] = (y[sa[i]] == y[sa[i - 1]] && y[sa[i] + j] == y[sa[i - 1] + j])
                     ? p - 1
                     : p++;
    }
  }
  for (int i = 0; i < n; i++) rnk[sa[i]] = i;
  for (int i = 0, k = 0; i < n - 1; lcp[rnk[i++]] = k) {
    if (k) k--;
    for (int j = sa[rnk[i] - 1]; s[i + k] == s[j + k]; k++)
      ;
  }
  return;
}
struct RMQ {
  int n, a[5005], mn[5005][15];
  void init(int _n) {
    n = _n;
    memset(a, 0, sizeof a);
  }
  void build() {
    for (int i = 1; i <= n; i++) mn[i][0] = a[i];
    for (int i = 1; (1 << i) <= n; i++) {
      int up = n - (1 << i) + 1;
      for (int j = 1; j <= up; j++) {
        mn[j][i] = min(mn[j][i - 1], mn[j + (1 << i - 1)][i - 1]);
      }
    }
    return;
  }
  int calc_min(int L, int R) {
    int k = 31 - __builtin_clz(R - L + 1);
    return min(mn[L][k], mn[R - (1 << k) + 1][k]);
  }
} A;
int main() {
  scanf("%d %d %d", &n, &a, &b);
  scanf("%s", s);
  strcpy(t, s);
  reverse(t, t + n);
  build(t);
  A.init(n + 1);
  for (int i = 1; i <= n; i++) {
    A.a[i] = lcp[i];
  }
  A.build();
  for (int i = 1; i <= n; i++) {
    dp[i] = 1e9;
    dp[i] = min(dp[i], dp[i - 1] + a);
    int now = rnk[n - i];
    for (int j = 1; j < i; j++) {
      int tmp = rnk[n - j], r;
      if (now < tmp)
        r = A.calc_min(now + 1, tmp);
      else
        r = A.calc_min(tmp + 1, now);
      if (r > 0) {
        dp[i] = min(dp[i], dp[max(j, i - r)] + b);
      }
    }
  }
  printf("%d\n", dp[n]);
  return 0;
}
