def PrimeList(N):
    P = [1] * (N + 1)
    P[0] = P[1] = 0
    for i in range(2, N + 1):
        if P[i]:
            for j in range(i + i, N + 1, i):
                P[j] = 0
    PL = []
    for i in range(N + 1):
        if P[i] == 1:
            PL.append(i)
    return PL

N = int(input())
PL = PrimeList(N)
SPL = set(PL)
ans = 0
for a in PL:
    a2 = a * a
    if a2 > N:
        break
    for b in PL:
        if b >= a2:
            break
        if a2 - b in SPL:
            ans += 1
print(ans)