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SICT1007 - Нийлбэр

Өгөгдсөн 4 оронтой тооны эхний 2 цифрийн ялгавар ба сүүлийн 2 цифрийн ялгаваруудын нийлбэрийг ол.

Input

4 оронтой эерэг бүхэл тоо өгөгдөнө.

Output

Нийлбэр

Example

Input:
1234

Output:
-2

Added by:B@TJ@RG@L
Date:2014-02-18
Time limit:1s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:C C++ 4.3.2 PYTHON

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