#include <bits/stdc++.h>
using namespace std;
const long long N = 5011;
const long long inf = 0x3f3f3f3f3f3f;
long long n, a, b, f[N], LCS[N][N];
namespace IO {
inline long long read() {
  long long x = 0;
  bool f = 0;
  char ch = getchar();
  for (; !isdigit(ch); ch = getchar()) f ^= (ch == '-');
  for (; isdigit(ch); ch = getchar()) x = (x << 3) + (x << 1) + (ch ^ 48);
  return f ? -x : x;
}
inline void write(long long x) {
  if (x < 0) putchar('-'), x = -x;
  if (x > 9) write(x / 10);
  putchar(x % 10 | 48);
}
inline void wrn(long long x) {
  write(x);
  putchar(' ');
}
inline void wln(long long x) {
  write(x);
  putchar('\n');
}
inline void wlnn(long long x, long long y) { wrn(x), wln(y); }
}  // namespace IO
using namespace IO;
int main() {
  string s;
  memset(f, 0x3f, sizeof(f));
  f[0] = 0;
  n = read() - 1, a = read(), b = read();
  cin >> s;
  for (register int i = (0); i <= (n); ++i)
    for (register int j = (0); j <= (n); ++j) {
      if (!i || !j)
        LCS[i][j] = (s[i] == s[j]) ? 1 : 0;
      else
        LCS[i][j] = (s[i] == s[j]) ? LCS[i - 1][j - 1] + 1 : 0;
    }
  for (register int i = (0); i <= (n); ++i) {
    f[i] = (i > 0) ? f[i - 1] + a : a;
    for (register int j = (0); j <= (i); ++j)
      f[i] = (((f[i]) <
               (f[i - (((i - j) < (LCS[i][j])) ? (i - j) : (LCS[i][j]))] + b))
                  ? (f[i])
                  : (f[i - (((i - j) < (LCS[i][j])) ? (i - j) : (LCS[i][j]))] +
                     b));
  }
  return wln(f[n]), 0;
}
