题号：NC207821
时间限制：C/C++/Rust/Pascal 1秒，其他语言2秒
空间限制：C/C++/Rust/Pascal 256 M，其他语言512 M
64bit IO Format: %lld
时间限制：C/C++/Rust/Pascal 1秒，其他语言2秒
空间限制：C/C++/Rust/Pascal 256 M，其他语言512 M
64bit IO Format: %lld
题目描述
There is a tower.
And there are N floors in this tower.
You need to climb to the N th floor from 1 th floor.You can only climb one floor at a time. You will get
gold coins at the 
floor. How many gold coins will you have when you climb to the N floor?
And there are N floors in this tower.
You need to climb to the N th floor from 1 th floor.You can only climb one floor at a time. You will get
输入描述:
There is an integer N indicate the floors the tower have.
输出描述:
print an integer represent the gold coins you can get when you arrive the N th floor.