b=[1,2,4,6,9,12]
s=1*1+2*2+3*2+4*3+5*3
i=3
m=5
while s < 10**18:
    for x in range(b[i-1],b[i]):
        for z in range(i):
            s+=len(b)*x
            b.append(x+b[m])
            m+=1
    i+=1

r=s=i=1
for n in range(2,10**6):
    while s < n**3:
        s+=(b[i+1]-b[i])*(i+1)
        i+=1
    r+=(n**3-(s-(b[i]-b[i-1])*i)-1)/i+b[i-1]

print r