#include <bits/stdc++.h>
using namespace std;
int n, s, k;
int read() {
  int s = 0, f = 1;
  char ch = getchar();
  while (ch < '0' || ch > '9') {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') {
    s = s * 10 + ch - '0';
    ch = getchar();
  }
  return s * f;
}
int a[101];
char c[101];
int dp[51][3000];
int main() {
  n = read(), s = read(), k = read();
  for (int i = 1; i <= n; ++i) a[i] = read();
  cin >> c + 1;
  memset(dp, 0x3f, sizeof(dp));
  for (int i = 1; i <= n; ++i) dp[i][a[i]] = abs(i - s);
  for (int i = 1; i <= k + 50; ++i) {
    for (int j = 1; j <= n; ++j) {
      for (int t = 1; t <= n; ++t) {
        if (c[j] != c[t] && a[t] > a[j])
          dp[t][i + a[t]] = min(dp[t][i + a[t]], dp[j][i] + abs(j - t));
      }
    }
  }
  int ans = 0x3f3f3f3f;
  for (int i = k; i <= k + 50; ++i) {
    for (int j = 1; j <= n; ++j) {
      ans = min(ans, dp[j][i]);
    }
  }
  if (ans == 0x3f3f3f3f)
    puts("-1");
  else
    cout << ans;
}
