def sieve(n):
    res = [True for _ in range(n + 1)]
    res[0] = False
    res[1] = False
    i = 2
    while i * i <= n:
        if res[i]:
            for j in range(i * 2, n + 1, i):
                res[j] = False
        i += 1
    return res

N = int(input())

S = sieve(N)

P = [i for i in range(N + 1) if S[i]]
R = []

for i in range(N + 1):
    if i**2 > 2 * N:
        break
    if S[i]:
        R.append(i**2)

res = 0

for p in P:
    for r in R:
        q = r - p
        if 0 < q <= N and S[q]:
            res += 1

print(res)