#include <bits/stdc++.h>
using namespace std;
int dp[51][2510];
pair<int, int> v[51];
string c, t;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  c = "0";
  for (int i = 0; i < 51; i++) {
    for (int j = 0; j < 2510; j++) {
      dp[i][j] = 1000000007;
    }
  }
  int n, s, K;
  cin >> n >> s >> K;
  int ans = 1000000007;
  for (int i = 1; i <= n; i++) {
    cin >> v[i].first;
    v[i].second = i;
  }
  sort(v + 1, v + n + 1);
  cin >> t;
  c += t;
  for (int i = 1; i <= n; i++) {
    dp[i][v[i].first] = abs(v[i].second - s);
    for (int j = 1; j < i; j++) {
      if (v[j].first != v[i].first && c[v[j].second] != c[v[i].second]) {
        for (int k = 1 + v[i].first; k < 2510; k++) {
          dp[i][k] = min(dp[i][k], (int)abs(v[j].second - v[i].second) +
                                       dp[j][k - v[i].first]);
        }
      }
    }
  }
  for (int i = 1; i <= n; i++) {
    for (int j = K; j < 2510; j++) {
      ans = min(ans, dp[i][j]);
    }
  }
  if (ans == 1000000007) ans = -1;
  cout << ans;
}
