L=int(input())
count=0
for i in range(1,L-1):
    for j in range(i,L-i):
        k=L-i-j
        if (k>=j and i+j>k and i+k>j and j+k>i):
            if (i==j and i==k):
                continue
            else:
                count=count+1
print(count)
/**************************************************************
	Problem: 1079
	User: admin
	Language: Python
	Result: Accepted
	Time:130 ms
	Memory:34480 kb
****************************************************************/