#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
using namespace std;

int main()
{
	int N;
	scanf("%d",&N);
	a=(1+N)*N/2;
	if(N<=100 && N>=0)
	{
		printf("%d",N);
	}
	else
	{
	}
	return 0;
}