#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
const long long mod2 = 1271309838631957LL;
long double PI = acosl(-1);
const long long inf = 1e15;
const int nmax = 5e3 + 10;
const int MAXLG = log2(nmax) + 1;
int dp[nmax];
vector<int> z_function(string s) {
  int n = (int)s.length();
  vector<int> z(n);
  for (int i = 1, l = 0, r = 0; i < n; ++i) {
    if (i <= r) z[i] = min(r - i + 1, z[i - l]);
    while (i + z[i] < n && s[z[i]] == s[i + z[i]]) ++z[i];
    if (i + z[i] - 1 > r) l = i, r = i + z[i] - 1;
  }
  return z;
}
int main() {
  ios::sync_with_stdio(false), cin.tie(0);
  int n, a, b;
  cin >> n >> a >> b;
  string s;
  cin >> s;
  for (int i = 1; i <= n; i++) dp[i] = INT_MAX;
  for (int i = 1; i <= n; i++) {
    string s2 = s.substr(i - 1, n + 1 - i);
    s2 += s.substr(0, i - 1);
    vector<int> v = z_function(s2);
    int mx = 0;
    for (int j = n + 1 - i; j < v.size(); j++) {
      mx = max(mx, v[j]);
    }
    for (int j = i, cnt = 1; cnt <= mx and j <= n; j++, cnt++)
      dp[j] = min(dp[j], dp[i - 1] + b);
    dp[i] = min(dp[i], dp[i - 1] + a);
  }
  cout << dp[n];
}
