/****************************************
#include <stdio.h>
int main()
{
char i, n, a, b;
scanf("%c %c", &a, &b);
printf("%c %c", a+1, b-1);
/// d e f g
return 0;
}
#include <stdio.h>
int main()
{
char i, n, a, b;
scanf("%c %c", &i, &n);
for(i=1; i<=n; i++)
{
printf("%c %c", i+1, n-1);
}
return 0;
}
*************************************/
/***********
#include <stdio.h>
int main()
{
char i, a, b;
scanf("%c %c", &a, &b);
for(i=a; i<=b; i++)
{
printf("%c ", i);
}
return 0;
}
**************/
///뭘 원하는 거니? 으아아아앙아앙아앙아아악 망했나바.......... djEmap..............
///온세상 사람들이여 봐라!!!!!! 이 우주최강 백하은이 해냈다!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
///나를 찬양 하라!!!!!!!!!!!!!!!!!!!!!!!!!!!
/********************************************************************
#include <stdio.h>
int main()
{
int i, n;
scanf("%d", &n);
for(i=1; i<=n; i++)
{
printf("*");
}
return 0;
}
*********************************************************************/
///내가 뭘 마마느든거지? 진작 이렇게 할 걸 싶지만...
///어쨌든!!!!!
///역시 위대한 백하은님은 오늘도 성공 하는 구만!!!!!!!!!!!!!!!!
/*********************************************************************
#include <stdio.h>
int main()
{
double i, a, b;
scanf("%lf %lf", &a, &b);
for(i=a; i<=b; i = i + 0.01)
{
printf("%.2lf ", i);
}
return 0;
}
********************************************************************/
/*
i=i+2
a+2
*/
/***************
x = x + 2
x는 x + 2다.
x + = 2
x에 2를 더해준다.
x++
x가 1만큼 증가 한다.
***************/
///후왓후!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 내가 해냈다!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
///백하은 짱!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
///우주최강 백하은!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
///천하무적 됐다 백하은!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
///난 짱!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 나는 최고!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
#include <stdio.h>
int main()
{
int i, a, sum=0;
scanf("%d", &a);
for(i=1; i<=a; i++)
{
if( i % 2 ==0)
{
sum += i;
// sum에 값 을 더해준다
}
}
printf("%d", sum);
// Sum을 출력한다
return 0;
}
//씨 씨 씨를 뿌리고 뭐더라?
//sum
// int a; -> a = NULL +1 -> (X)