# Jaccard index P67731

Statement

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The Jaccard index is a statistic used for comparing the similarity and diversity of two sets. Namely, the Jaccard index J(A,B) of A and B is

J(A,B) =
 ∣ A⋂ B∣ ∣ A⋃ B∣
.

For example, the Jaccard index of the sets {1,2,3} and {3,4} is 0.25.

Write a program to compute the Jaccard index of pairs of sets of integers.

Input

The input consists of several cases. Each case starts describes two sets A and B. The first set A starts with its cardinality m ≥ 0 and then follow its m integer elements in strictly increasing order. The second set B starts with its cardinality m ≥ 0 and then follow its n integer elements in strictly increasing order. For each case, m+n≥1.

Output

For each case in the input, print the Jaccard index of its two sets in a different line with 3 digits of precision.

Hint

• Basic set theory may save you some valuable coding time.
• Use cout.setf(ios::fixed); cout.precision(3); at the beginning of your program to print real numbers with 3 digits of precision.

Public test cases
• Input

```3   1 2 3
2   3 4

11  -9 -7 -5 -1 3 4 5 8 11 17 19
11  -8 -5 -4 1 3 6 8 9 11 12 17

0
3   1 2 3
```

Output

```0.250
0.294
0.000
```
• Information
Author
Guillem Godoy, Jordi Petit
Language
English
Translator
Original language
Catalan
Other languages
Catalan
Official solutions
C++
User solutions
C++ Python