count=0
n=int(input())
def f(n):
    if n<=3:
        return n
    elif n>3 and n%2==0:
        return 2*n*n+f(n-1)
    else:
        return n*n*n+n+f(n-1)

for i in range(1,300):
    n=i
    if f(i)<10**7:
        count+=1
print(count)