题目描述
Three Best Friends $AMAN$ , $AKBAR$ , $ANTHONY$ are planning to go to “GOA” , but just like every other goa trip plan there is a problem to their plan too.
Their parents will only give permission if they can solve this problem for them
They are a given a number N and they have to calculate the total number of triplets (x ,y ,z)
Satisfying the given condition y * x +z=n.
For ex if N=3
Then there exist 3 triplets( x ,y ,z): (1,1,2) , (1,2,1) , (2,1,1) which satisfy the condition
Help the group to get permission for the trip
-----Input:-----
- First line will contain the number $N$.
-----Output:-----
the possible number of triplets satisfying the given condition
-----Constraints-----
- $2 \leq N \leq 10^6$
-----Sample Input:-----
3
-----Sample Output:-----
3
-----EXPLANATION:-----
there exist 3 triplets ( x ,y ,z): (1,1,2) , (1,2,1) , (2,1,1) which satisfy the condition
输入格式
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输出格式
见题面