#include <bits/stdc++.h>
using namespace std;
const long long INFLL = 1e18;
const int MAXN = 1e6 + 100;
const long long INF = 1e9;
const long long mod1 = 1e9 + 7;
const long long mod2 = 2e9 + 11;
int dp[5001];
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int n, a, b;
  cin >> n >> a >> b;
  string s;
  cin >> s;
  dp[0] = 0;
  dp[1] = a;
  for (int j = 2; j <= n; j++) dp[j] = INF;
  if (s.size() > 1 && s[0] == s[1]) dp[2] = min(dp[2], min(a + b, a + a));
  for (int i = 2; i <= n; i++) {
    dp[i] = min(dp[i], dp[i - 1] + a);
    if (i == n) continue;
    string t = "";
    for (int j = i; j < n; j++) {
      t += s[j];
    }
    t += '#';
    int g = t.size();
    for (int j = 0; j < i; j++) t += s[j];
    vector<int> pi(t.size(), 0);
    for (int j = 1; j < t.size(); j++) {
      int f = pi[j - 1];
      while (t[j] != t[f] && f != 0) f = pi[f - 1];
      if (t[f] == t[j]) f++;
      pi[j] = f;
      if (j >= g) {
        int x = f;
        if (x > 0) {
          dp[i + x] = min(dp[i + x], dp[i] + b);
        }
      }
    }
  }
  cout << dp[n];
}
