#include <bits/stdc++.h>
using namespace std;
const int N = 55;
const int M = 6060;
const int inf = (int)1e9;
int dp[N][M];
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n, s, m;
  cin >> n >> s >> m;
  vector<int> a(n + 1);
  for (int i = 0; i < n; i++) {
    cin >> a[i + 1];
  }
  cin.ignore();
  map<char, int> mp = {{'R', 0}, {'G', 1}, {'B', 2}};
  vector<int> color(n + 1);
  string colors;
  cin >> colors;
  for (int i = 0; i < n; i++) {
    color[i + 1] = mp[colors[i]];
  }
  for (int i = 0; i <= n; i++) {
    for (int j = 0; j < M; j++) {
      dp[i][j] = inf;
    }
  }
  vector<int> p(n + 1);
  for (int i = 1; i <= n; i++) {
    p[i] = i;
  }
  sort(p.begin() + 1, p.end(),
       [&](const int &i, const int &j) { return a[i] > a[j]; });
  dp[0][0] = 0;
  for (int i = 1; i <= n; i++) {
    for (int j = 0; j < M; j++) {
      if (j - a[p[i]] < 0) {
        continue;
      }
      for (int k = 0; k < i; k++) {
        if (k == 0 || a[p[k]] > a[p[i]]) {
          if (k == 0 || color[p[k]] != color[p[i]]) {
            dp[i][j] = min(dp[i][j],
                           dp[k][j - a[p[i]]] + (k > 0 ? abs(p[i] - p[k]) : 0));
          }
        }
      }
    }
  }
  int ans = inf;
  for (int i = 1; i <= n; i++) {
    for (int j = m; j < M; j++) {
      ans = min(ans, dp[i][j] + abs(s - p[i]));
    }
  }
  if (ans < inf) {
    cout << ans << '\n';
  } else {
    cout << "-1\n";
  }
  return 0;
}
