#include <bits/stdc++.h>
using namespace std;
int ar[55], DP[55][2005];
int N, S, K;
int main() {
  cin >> N >> S >> K;
  for (int i = 0; i < N; i++) cin >> ar[i];
  string str;
  cin >> str;
  int ans = 2000000009;
  for (int i = 0; i < 55; i++) {
    for (int j = 0; j < 2005; j++) {
      DP[i][j] = 2000000009;
    }
  }
  for (int i = 0; i < N; i++) DP[i][ar[i]] = abs(S - 1 - i);
  for (int j = 0; j < 2005; j++) {
    for (int i = 0; i < N; i++) {
      for (int k = 0; k < N; k++) {
        if (ar[k] > ar[i] && str[k] != str[i]) {
          DP[k][j + ar[k]] = min(DP[k][j + ar[k]], DP[i][j] + abs(k - i));
        }
      }
    }
  }
  for (int i = 0; i < 55; i++)
    for (int j = K; j < 2005; j++) ans = min(ans, DP[i][j]);
  cout << (ans == 2000000009 ? -1 : ans) << endl;
  return (0);
}
