#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  int n, s, k, a[55], dp[55][2505];
  cin >> n >> s >> k;
  for (int i = 0; i < n; i++) cin >> a[i];
  string s1;
  cin >> s1;
  priority_queue<pair<int, pair<int, int> > > q;
  s--;
  for (int i = 0; i < 55; i++)
    for (int j = 0; j < 2505; j++) dp[i][j] = 1e7 + 7;
  for (int i = 0; i < n; i++) {
    dp[i][a[i]] = abs(i - s);
    q.push(make_pair(abs(i - s), make_pair(i, a[i])));
  }
  while (!q.empty()) {
    pair<int, pair<int, int> > p = q.top();
    q.pop();
    int dd = p.first;
    int at = p.second.first;
    int choc = p.second.second;
    for (int i = 0; i < n; i++) {
      if (a[i] > a[at] && s1[i] != s1[at]) {
        int dis = abs(i - at);
        if (dp[at][choc] + dis < dp[i][choc + a[i]]) {
          dp[i][choc + a[i]] = dp[at][choc] + dis;
          q.push(make_pair(-dp[i][choc + a[i]], make_pair(i, choc + a[i])));
        }
      }
    }
  }
  int ans = 1e7 + 7;
  for (int i = 0; i < n; i++)
    for (int j = k; j <= 2505; j++) ans = min(ans, dp[i][j]);
  if (ans > 1e6)
    cout << "-1";
  else
    cout << ans;
  return 0;
}
