#include <bits/stdc++.h>
using namespace std;
const long long int mod1 = 998244353;
const long long int mod = 1e9 + 7;
const long long int N = 1000005;
struct dat {
  long long int e, s, f;
  dat(long long int s_, long long int e_, long long int f_)
      : s(s_), e(e_), f(f_) {}
  bool operator<(const dat &a) { return s < a.s; }
};
bool cmp(long long int a, long long int b) { return a < b; }
long long int a[55];
long long int dp[55][3005];
char t[55];
void solve() {
  long long int n, st, k;
  cin >> n >> st >> k;
  for (long long int i = (1); i <= (n); ++i) cin >> a[i];
  cin >> t;
  for (long long int j = (1); j <= (n); ++j)
    for (long long int p = (1); p <= (k + 50); ++p) dp[j][p] = 1e9;
  for (long long int i = (1); i <= (n); ++i) dp[i][a[i]] = abs(i - st);
  for (long long int p = (1); p <= (k + 50); ++p)
    for (long long int i = (1); i <= (n); ++i)
      for (long long int j = (1); j <= (n); ++j)
        if (t[i - 1] != t[j - 1] && a[i] < a[j])
          dp[j][p + a[j]] = min(dp[j][p + a[j]], dp[i][p] + abs(i - j));
  long long int ans = 1e18;
  for (long long int i = (1); i <= (n); ++i)
    for (long long int j = (k); j <= (k + 50); ++j) ans = min(ans, dp[i][j]);
  if (ans == 1e9) ans = -1;
  cout << ans;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long int t = 1;
  while (t--) {
    solve();
    cout << "\n";
  }
  return 0;
}
