#include <bits/stdc++.h>
int dx[] = {0, 0, 1, -1, 1, -1, 1, -1};
int dy[] = {1, -1, 0, 0, -1, 1, 1, -1};
const double PI = acos(-1), EPS = 1e-7;
const int OO = 0x3f3f3f3f, N = 2e5 + 5, mod = 1e9 + 7;
using namespace std;
long long gcd(long long x, long long y) { return (!y) ? x : gcd(y, x % y); }
long long lcm(long long x, long long y) { return ((x / gcd(x, y)) * y); }
void file() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
}
int n, s, k;
vector<int> v;
string ss;
int dp[55][2005];
int solve(int idx, int kk) {
  if (kk <= 0) return 0;
  int &ret = dp[idx][kk];
  if (~ret) return ret;
  ret = OO;
  for (int i = 0; i < n; i++) {
    if (i != idx && v[i] > v[idx] && ss[i] != ss[idx])
      ret = min(ret, solve(i, kk - v[i]) + abs(i - idx));
  }
  return ret;
}
int main() {
  file();
  cin >> n >> s >> k;
  v.resize(n);
  for (int i = 0; i < n; i++) cin >> v[i];
  cin >> ss;
  memset(dp, -1, sizeof(dp));
  int ans = OO;
  for (int i = 0; i < n; i++) {
    ans = min(ans, solve(i, k - v[i]) + abs(s - i - 1));
  }
  if (ans == OO) ans = -1;
  cout << ans << '\n';
}
