#include <bits/stdc++.h>
using namespace std;
const long long MAXN = 5000 + 39;
long long poss[MAXN][MAXN], dp[MAXN];
vector<long long> get_z(string &second) {
  long long n = second.size();
  vector<long long> z(n);
  long long l = 0, r = 0;
  for (long long i = 1; i < n; ++i) {
    if (i <= r) z[i] = min(r - i + 1, z[i - l]);
    while (second[z[i]] == second[i + z[i]]) ++z[i];
    if (i + z[i] - 1 > r) {
      r = i + z[i] - 1;
      l = i;
    }
  }
  return z;
}
bool ok(string &second, long long i, long long m) {
  string res = second.substr(i, m) + "#" + second.substr(0, i);
  vector<long long> z = get_z(res);
  bool first = 0;
  for (long long i = 0; i < z.size(); ++i) first |= z[i] == m;
  return first;
}
void dfs(long long l, long long r) {
  if (l > r) return;
  poss[l][r] = 1;
  if (!poss[l][r - 1]) dfs(l, r - 1);
  if (!poss[l + 1][r - 1]) dfs(l + 1, r - 1);
  if (!poss[l + 1][r]) dfs(l + 1, r);
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long n, a, b;
  cin >> n >> a >> b;
  string second;
  cin >> second;
  for (long long i = 1; i < n; ++i) {
    long long l = 0, r = i + 1;
    while (r - l > 1) {
      long long m = (l + r) / 2;
      if (ok(second, i, m))
        l = m;
      else
        r = m;
    }
    dfs(i, i + l - 1);
  }
  dp[0] = a;
  for (long long r = 1; r < n; ++r) {
    dp[r] = dp[r - 1] + a;
    for (long long t = 0; t < r; ++t)
      if (poss[t + 1][r]) dp[r] = min(dp[r], dp[t] + b);
  }
  cout << dp[n - 1] << "\n";
  return 0;
}
