n = int(input())
r = [1]*(n+1)
ans = 0
for i in range(1,n+1):
    if r[i] == 0: continue
    c = 0
    for j in range(1,n+1):
        if i*j*j > n: break
        c += 1
        r[i*j*j] = 0
    ans += c*c
print(ans)