def solve(N):
    primes = primes2(N)
    dp = [0] * (N + 1)
    dp[0] = 1
    cumsum = 0
    for p in primes:
        cumsum += p
        for i in range(min(cumsum, N), p - 1, -1):
            tmp = dp[i - p]
            if tmp and tmp + 1 > dp[i]:
                dp[i] = tmp + 1
    return dp[N] - 1

N = int(input())
print(solve(N))