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Problem 4805. -- 欧拉函数求和

4805: 欧拉函数求和

Time Limit: 15 Sec  Memory Limit: 256 MB
Submit: 1122  Solved: 629
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Description

给出一个数字N,求sigma(phi(i)),1<=i<=N

Input

正整数N。N<=2*10^9

Output

输出答案。

Sample Input

10

Sample Output

32

HINT

Source

By FancyCoder

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