#include <bits/stdc++.h>
using namespace std;
int N, S, K;
int arr[51];
string str;
int solve() {
  int ans = 2001001001;
  int dp[2501][51];
  for (int i = 0; i <= 2500; i++)
    for (int j = 0; j < N; j++) dp[i][j] = 2001001001;
  for (int i = 0; i < N; i++) {
    dp[arr[i]][i] = abs(i - S);
    if (arr[i] >= K) ans = min(ans, abs(i - S));
  }
  for (int i = 1; i <= 2500; i++) {
    for (int j = 0; j < N; j++) {
      if (dp[i][j] != 2001001001) {
        for (int k = 0; k < N; k++) {
          if (arr[k] > arr[j] && str[j] != str[k]) {
            dp[i + arr[k]][k] = min(dp[i + arr[k]][k], dp[i][j] + abs(j - k));
            if (i + arr[k] >= K) ans = min(ans, dp[i + arr[k]][k]);
          }
        }
      }
    }
  }
  return ans;
}
int main() {
  cin >> N >> S >> K;
  S--;
  for (int i = 0; i < N; i++) cin >> arr[i];
  cin >> str;
  int ans = 2001001001;
  ans = min(ans, solve());
  if (ans == 2001001001)
    cout << -1 << endl;
  else
    cout << ans << endl;
  return 0;
}
