#include <bits/stdc++.h>
using namespace std;
const long long inf = 3e18 + 5;
const int mod = 1e9 + 7;
int ctz(int x) { return __builtin_ctz(x); }
int clz(int x) { return __builtin_clz(x); }
int n, a, b;
string s;
void init(string& P, vector<int>& b) {
  int i = 0, j = -1;
  b[0] = -1;
  while (i < int(P.size())) {
    while (j >= 0 && P[i] != P[j]) j = b[j];
    b[++i] = ++j;
  }
}
bool kmp(string& T, string& P, vector<int>& b) {
  vector<int> ret;
  int i = 0, j = 0;
  while (i < int(T.size())) {
    while (j >= 0 && T[i] != P[j]) j = b[j];
    ++i;
    ++j;
    if (j == int(P.size())) {
      return true;
    }
  }
  return false;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cin >> n >> a >> b;
  cin >> s;
  vector<int> dp(n, mod);
  dp[0] = a;
  string text = s.substr(0, 1);
  for (int i = 1; i < n; i++) {
    dp[i] = min(dp[i], dp[i - 1] + a);
    int lo = i, hi = n;
    while (lo < hi) {
      int mid = (lo + hi + 1) / 2;
      string pattern = s.substr(i, mid - i);
      vector<int> b(int(pattern.size()) + 1);
      init(pattern, b);
      if (kmp(text, pattern, b)) {
        lo = mid;
      } else {
        hi = mid - 1;
      }
    }
    text += s[i];
    if (i == lo) continue;
    dp[lo - 1] = min(dp[lo - 1], dp[i - 1] + b);
  }
  cout << dp[n - 1];
}
