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

public class Lab01B {

  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 numberStraights = 0;
    for (int trial = 0; trial < TRIALS; trial++) {
      for (Die d : dice) {
        d.roll();
      }

      // Sort the dice; this makes checking for the straight much easier!
      Collections.sort(dice);

      // For a large straight, we loop through the dice starting at the
      // die in the second position in the list and finishing at the die
      // in the last position of the list.
      // Each time through the loop we compare the die in the current
      // position to the die in the position before it; if the value
      // of the die in the current position is not one larger than the
      // die in the position before it there cannot be a straight.
      boolean isStraight = true;
      for (int i = 1; i < N; i++) {
        if (dice.get(i).getValue() != dice.get(i - 1).getValue() + 1) {
          isStraight = false;
        }
      }
      if (isStraight) {
        numberStraights++;
      }
    }
    System.out.printf("%.6f%n", (double) numberStraights / TRIALS);
  }
}