Yuanfang，what do you think ?
Yuanfang is the best student in the class. Every time when the teacher comes up with a hard problem and it seems no student can solve it, He always says: "Yuanfang , what do you think?".
One day, They had a math class,The teacher said:”Let’s calculate the sum of 1^2+2^2…+n^2，Yuanfang, what do you think?"
Yuanfang wanted to solve this problem quickly. So he came to you, the only programmer he knows, for help.
You should write a program to calculate SUM(n)=1^2+2^2…+n^2 to help him.
Each case has an integer n (1≤n≤1000) in a line.