#include <bits/stdc++.h>
using namespace std;
const long long N = 2055;
inline long long read() {
  long long s = 0, w = 1;
  register char ch = getchar();
  while (ch < '0' || ch > '9') {
    if (ch == '-') w = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9')
    s = (s << 3) + (s << 1) + (ch ^ 48), ch = getchar();
  return s * w;
}
long long n, S, K, F[N][N];
char s[N];
struct Node {
  long long w, id;
} a[N];
inline bool cp(Node x, Node y) { return x.w < y.w; }
signed main() {
  n = read(), S = read(), K = read();
  for (register long long i = 1; i <= n; i++) a[i].w = read(), a[i].id = i;
  scanf("%s", s + 1);
  sort(a + 1, a + 1 + n, cp);
  memset(F, 0x3f, sizeof(F));
  for (register long long i = 1; i <= n; i++) {
    for (register long long j = 0; j <= a[i].w; j++) F[i][j] = abs(a[i].id - S);
    for (register long long j = 1; j <= n; j++) {
      if (s[a[i].id] == s[a[j].id] || a[j].w >= a[i].w) continue;
      for (register long long k = K; k >= a[i].w; k--)
        F[i][k] = min(F[i][k], F[j][k - a[i].w] + abs(a[i].id - a[j].id));
    }
  }
  long long Ans = 1e18;
  for (register long long i = 1; i <= n; i++) Ans = min(Ans, F[i][K]);
  printf("%lld\n", (Ans >= 1e18) ? (-1) : (Ans));
  return 0;
}
