#include <bits/stdc++.h>
using namespace std;
const int N = 55;
const int K = 4003;
int n, s, k;
int A[N];
string X;
int dp[N][K];
const int oo = 1e9;
int comp(int i, int t) {
  if (t <= 0) return 0;
  if (dp[i][t] != -1) return dp[i][t];
  int res = oo;
  for (int j = 0; j < n; ++j) {
    if (X[i] != X[j] and A[j] > A[i]) {
      auto u = comp(j, t - A[j]);
      if (u != oo) res = min(res, abs(j - i) + u);
    }
  }
  return dp[i][t] = res;
}
int main(int argc, char const *argv[]) {
  cin >> n >> s >> k;
  s--;
  for (int i = 0; i < n; ++i) {
    cin >> A[i];
  }
  for (int i = 0; i < N; ++i) {
    for (int j = 0; j < K; ++j) {
      dp[i][j] = -1;
    }
  }
  cin >> X;
  int ans = oo;
  for (int i = 0; i < n; ++i) {
    ans = min(ans, abs(i - s) + comp(i, k - A[i]));
  }
  ans = (ans >= oo) ? -1 : ans;
  cout << ans << endl;
  return 0;
}
