from collections import defaultdict

def eratosthenes(N):
    P = []
    d = defaultdict(int)
    for p in range(2,N+1):
        if d[p] == 1:
            continue
        P.append(p)
        for q in range(1,N//p+1):
            d[p*q] = 1
    return P

d = defaultdict(int)
N = int(input())
P = eratosthenes(300000)
Q = [2]
S = []
ans = 0
for i in range(2,len(P)):
  c = P[i]
  if c > N:
    break
  for p in Q:
    q = p + P[i-1]
    d[q] += 1
  Q.append(P[i-1])
  for p in P:
    q = p - c
    ans += d[q]
print(ans)