#include <bits/stdc++.h>
using namespace std;
const int N = 5005, mod1 = 1e9 + 9, base1 = 31, mod2 = 1e9 + 7, base2 = 59;
bool pre[N][N];
int hash1[N][N], hash2[N][N];
void buildPreHash(const string &x) {
  int n = ((int)((x).size()));
  for (int i = 0; i < n; i++) {
    long long h1 = 1, h2 = 1;
    for (int j = i; j < n; j++) {
      h1 = (h1 * base1 + x[j] - 'a') % mod1;
      hash1[i][j] = h1;
      h2 = (h2 * base2 + x[j] - 'a') % mod2;
      hash2[i][j] = h2;
    }
  }
  for (auto i = 0; i < (long long)(n); i++) {
    unordered_set<int> h1, h2;
    for (int j = 0; i + j < n; j++) {
      if (j - (i + 1) >= 0) {
        h1.insert(hash1[j - (i + 1)][j - 1]);
        h2.insert(hash2[j - (i + 1)][j - 1]);
      }
      if (h1.find(hash1[j][j + i]) != h1.end() &&
          h2.find(hash2[j][i + j]) != h2.end())
        pre[j][i + j] = 1;
    }
  }
}
string x;
int n, a, b;
int memo[N];
int solve(int idx) {
  if (idx == n) return 0;
  int &ret = memo[idx];
  if (~ret) return ret;
  ret = a + solve(idx + 1);
  for (int j = idx; j < n; j++) {
    if (pre[idx][j]) ret = min(ret, b + solve(j + 1));
  }
  return ret;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> n >> a >> b;
  cin >> x;
  buildPreHash(x);
  memset(memo, -1, sizeof memo);
  cout << solve(0) << '\n';
  return 0;
}
