#include <bits/stdc++.h>
using namespace std;
double PI = 3.1415926535897932384626;
long long n, s, k;
long long ri[52];
char co[52];
long long dp[2052][52];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cin >> n >> s >> k;
  for (long long i = 1; i <= n; i++) cin >> ri[i];
  for (long long i = 1; i <= n; i++) cin >> co[i];
  for (long long i = 0; i < 2052; i++) {
    for (long long j = 0; j < 52; j++) {
      dp[i][j] = 1e15;
    }
  }
  for (long long i = 1; i <= n; i++) {
    dp[ri[i]][i] = abs(s - i);
  }
  for (long long k1 = 0; k1 <= (k + 50); k1++) {
    for (long long i = 1; i <= n; i++) {
      if (k1 - ri[i] >= 0) {
        for (long long j = 1; j <= n; j++) {
          if (i == j || co[i] == co[j]) continue;
          if (ri[i] > ri[j]) {
            dp[k1][i] = min(dp[k1][i], dp[k1 - ri[i]][j] + abs(i - j));
          }
        }
      }
    }
  }
  long long ans = 1e15;
  for (long long k1 = k; k1 <= (k + 50); k1++) {
    for (long long i = 1; i <= n; i++) {
      ans = min(ans, dp[k1][i]);
    }
  }
  if (ans == 1e15)
    cout << -1;
  else
    cout << ans;
  return 0;
}
