from math import floor, sqrt
n = int(input())
rn = int(n**0.5)+1
base = [i for i in range(n+1)]
use = [0]*(rn+1)

for i in range(2,rn+1):
    if use[i]:
        continue
    for j in range(i,rn+1,i):
        use[j] = 1
    j = i**2
    w = i**2
    while j <= n:
        k = j
        while k <= n:
            base[k] //= w
            k += j
        j *= w

ans = 0
for i in range(1,n+1):
    ans += floor(sqrt(n/base[i]))
print(ans)