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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