#include <bits/stdc++.h>
using namespace std;
template <typename T>
void read(T &x) {
  x = 0;
  char ch = getchar();
  int fh = 1;
  while (ch < '0' || ch > '9') {
    if (ch == '-') fh = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') x = x * 10 + ch - '0', ch = getchar();
  x *= fh;
}
template <typename T>
void write(T x) {
  if (x < 0) x = -x, putchar('-');
  if (x > 9) write(x / 10);
  putchar(x % 10 + '0');
}
template <typename T>
void writeln(T x) {
  write(x);
  puts("");
}
int n, s, k;
int r[55];
char c[55];
int dp[55][2505];
queue<pair<int, int> > q;
signed main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> s >> k;
  for (int i = 1; i <= n; i++) cin >> r[i];
  cin >> c + 1;
  memset(dp, 0x3f, sizeof(dp));
  for (int i = 1; i <= n; i++) {
    dp[i][r[i]] = abs(s - i);
    q.push(make_pair(i, r[i]));
  }
  while (!q.empty()) {
    pair<int, int> p = q.front();
    q.pop();
    for (int i = 1; i <= n; i++) {
      if (r[i] > r[p.first] && c[i] != c[p.first] &&
          dp[i][p.second + r[i]] > dp[p.first][p.second] + abs(i - p.first)) {
        dp[i][p.second + r[i]] = dp[p.first][p.second] + abs(i - p.first);
        q.push(make_pair(i, p.second + r[i]));
      }
    }
  }
  int ans = 1000000007;
  for (int i = 1; i <= n; i++) {
    for (int j = k; j <= 2500; j++) ans = min(ans, dp[i][j]);
  }
  if (ans == 1000000007) ans = -1;
  cout << ans << endl;
  return 0;
}
