Time Limit: 3000 MS Memory Limit: 65536 K

Description

Tailmon has just finished the homework of "addition and subtraction£®the number less than 10^8£©", please help her check. The format is a+b=c or a-b=c (Hint: c can be "?" , which means Tailmon cannot calculate).

Input

The input contains no more than 100 lines, "EOF" to end of file . Each line contains a subject, and does not contain any blank characters. Input all integer shall not contain leading 0.

Output

Output only a line, contains the number that Tailmon got the right answer.

Sample Input

1+2=3
3-1=5
6+7=?
99-0=99

Sample Output

2

Author

yjx