#include<bits/stdc++.h>
using namespace std;
	int main(){
	int n,s=0,i=1;
	cin>>n;
	while(i<=100){
	s=i+s;
	i++;
	
	
	
	}
	
	cout<<s;
	
	
	return 0;}
	
	
	
	
	







/**************************************************************
	Problem: 1002
	User: zhangchenhao
	Language: C++
	Result: Wrong Answer
****************************************************************/