import cse1030.Die;
import java.util.Collections;
import java.util.List;
import java.util.ArrayList;

public class Lab01D {

  public static void main(String[] args) {

    final int N = 5;

    // Create a list of N dice to roll
    List<Die> dice = new ArrayList<Die>();
    for (int i = 0; i < N; i++) {
      dice.add(new Die());
    }

    final int TRIALS = 1000000;
    int numberFullHouse = 0;
    for (int trial = 0; trial < TRIALS; trial++) {
      for (Die d : dice) {
        d.roll();
      }
      // Sorting makes checking for a full house much easier!
      Collections.sort(dice);

      // A full house can only occur if the sorted dice have one of the
      // two configurations:
      //
      // X-X-Y-Y-Y
      //
      // or
      //
      // X-X-X-Y-Y
      //
      // where X and Y indicate arbitrary dice values.
      int first = dice.get(0).getValue();
      int second = dice.get(1).getValue();
      int third = dice.get(2).getValue();
      int fourth = dice.get(3).getValue();
      int fifth = dice.get(4).getValue();
      boolean isFullHouse =
          (first == second && third == fifth) ||
          (first == third && fourth == fifth);
      if (isFullHouse) {
        numberFullHouse++;
      }
    }
    System.out.printf("%.6f%n", (double) numberFullHouse / TRIALS);
  }
}