#include <bits/stdc++.h>
using namespace std;
const int inf = 0x7fffffff;
const double eps = 1e-10;
const double pi = acos(-1.0);
inline int read() {
  int x = 0, f = 1;
  char ch;
  ch = getchar();
  while (ch < '0' || ch > '9') {
    if (ch == '-') f = 0;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') {
    x = (x << 1) + (x << 3) + (ch & 15);
    ch = getchar();
  }
  if (f)
    return x;
  else
    return -x;
}
const int N = 5010;
int n, a, b;
int val[N], nex[N], ans;
char s[N];
int main() {
  n = read();
  a = read();
  b = read();
  memset(val, 0x3f, sizeof(val));
  val[0] = 0;
  scanf("%s", s + 1);
  for (int i = 1; i <= n; i++) {
    val[i] = min(val[i], val[i - 1] + a);
    nex[i] = i - 1;
    int p = i - 1;
    for (int j = i + 1; j <= n; j++) {
      while (p >= i && s[j] != s[p + 1]) p = nex[p];
      if (s[j] == s[p + 1]) p++;
      nex[j] = p;
    }
    p = i - 1;
    for (int j = 1; j <= i - 1; j++) {
      while (p >= i && s[j] != s[p + 1]) p = nex[p];
      if (s[j] == s[p + 1]) p++;
      if (p >= i) val[p] = min(val[p], val[i - 1] + b);
    }
  }
  printf("%d\n", val[n]);
  return 0;
}
