Write a program that, given two intervals, computes the interval corresponding to their intersection, or tells that it is empty.

**Input**

Input consists of four integer numbers *a*_{1}, *b*_{1}, *a*_{2}, *b*_{2}
that represent the intervals [*a*_{1},*b*_{1}] and [*a*_{2},*b*_{2}].
Assume *a*_{1}≤ *b*_{1} and *a*_{2}≤ *b*_{2}.

**Output**

Print “`[]`” if their intersection is empty,
or “`[`*x*`,`*y*`]`” if this is their non-empty intersection.

Public test cases

**Input**

20 30 10 40

**Output**

[20,30]

**Input**

10 20 10 20

**Output**

[10,20]

**Input**

20 30 10 20

**Output**

[20,20]

**Input**

10 20 30 40

**Output**

[]

Information

- Author
- Salvador Roura
- Language
- English
- Translator
- Carlos Molina
- Original language
- Catalan
- Other languages
- Catalan
- Official solutions
- C++ Java Python
- User solutions
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