Odd or Even

Discussions Toph Problems
22

what is wrong here???/

#include <stdio.h>
#include <stdlib.h>
#include <math.h>


int main()
{
    long long int n, i, j, ce, co;
    scanf("%lld\n", &n);
    if (n % 2 == 0) {
        i = n / 2;
        j = n / 2;
    }
    else {
        i = n / 2;
        j = n / 2;
        j += 1;
    }
    ce = i * (i + 1);
    co = j * j;
    long long int d = abs(ce - co);
    printf("%lld\n", d);
}