#include <bits/stdc++.h>
using namespace std;
long long modi[5005], modi2[5005], HASH, HASH2, pdp[5005], pdp2[5005], hell2;
long long dp[5005];
long long expo(long long base, long long exponent, long long mod) {
  long long ans = 1;
  while (exponent != 0) {
    if ((exponent & 1) == 1) {
      ans = ans * base;
      ans = ans % mod;
    }
    base = base * base;
    base %= mod;
    exponent >>= 1;
  }
  return ans % mod;
}
long long modInv(long long a, long long m) { return expo(a, m - 2, m); }
void solve() {
  long long n, a, b;
  HASH = 937;
  HASH2 = 991;
  hell2 = 1000000021;
  cin >> n >> a >> b;
  long long pw = 1;
  for (long long int i = 0; i < n + 1; i++) {
    pdp[i] = pw;
    modi[i] = modInv(pw, 1000000007);
    pw = (pw * HASH) % 1000000007;
  }
  pw = 1;
  for (long long int i = 0; i < n + 1; i++) {
    pdp2[i] = pw;
    modi2[i] = modInv(pw, hell2);
    pw = (pw * HASH2) % hell2;
  }
  for (long long int i = 0; i < n; i++) dp[i] = hell2;
  string s;
  cin >> s;
  vector<long long int> v(n + 1, 0), v2(n + 1, 0);
  for (long long int i = 0; i < n; i++) {
    v[i] = ((s[i] - 'a' + 1) * pdp[n - 1 - i]) % 1000000007;
  }
  for (long long int i = 0; i < n; i++) {
    v2[i] = ((s[i] - 'a' + 1) * pdp2[n - 1 - i]) % hell2;
  }
  for (long long i = n - 2; i >= 0; i--) v[i] = (v[i] + v[i + 1]) % 1000000007;
  for (long long i = n - 2; i >= 0; i--) v2[i] = (v2[i] + v2[i + 1]) % hell2;
  dp[0] = a;
  for (long long int i = 1; i < n; i++) {
    dp[i] = min(dp[i], a + dp[i - 1]);
    long long tp = 1;
    long long vl =
        (((v[i] - v[i + 1] + 1000000007) % 1000000007) * modi[n - i - 1]) %
        1000000007;
    long long vl2 =
        (((v2[i] - v2[i + 1] + hell2) % hell2) * modi2[n - i - 1]) % hell2;
    for (long long int j = 0; j < i; j++) {
      long long pvl = (((v[j - tp + 1] - v[j + 1] + 1000000007) % 1000000007) *
                       modi[n - j - 1]) %
                      1000000007;
      long long pvl2 =
          (((v2[j - tp + 1] - v2[j + 1] + hell2) % hell2) * modi2[n - j - 1]) %
          hell2;
      if (vl == pvl && vl2 == pvl2) {
        dp[i + tp - 1] = min(dp[i + tp - 1], dp[i - 1] + b);
        tp++;
        vl = (((v[i] - v[i + tp] + 1000000007) % 1000000007) *
              modi[n - i - tp]) %
             1000000007;
        vl2 = (((v2[i] - v2[i + tp] + hell2) % hell2) * modi2[n - i - tp]) %
              hell2;
      }
    }
  }
  cout << dp[n - 1];
  return;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int TESTS = 1;
  while (TESTS--) {
    solve();
  }
  cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
  return 0;
}
