N = int(input())

prime = [2,3,5,7,11,13,17,19,23,29,31,37]
n = len(prime)

ans = 0
dat = list(range(N+1))
dat2 = [0] * (N + 1)
for i in range(n):
    p = prime[i]
    for j in range(p,N+1,p):
        while dat[j] % p == 0:
            dat[j] //= p
        dat2[j] |= 1 << i
for j in range(2,N+1):
    if dat[j] == j:
        ans += j
dp = [0] * (1 << n)
for j in range(2,N+1):
    dp[dat2[j]] = j
for bit in range(1,1 << n):
    T = bit
    while T:
        T -= 1
        T &= bit
        if dp[bit] < dp[T] + dp[bit ^ T]:
            dp[bit] = dp[T] + dp[bit ^ T]
print(ans + max(dp))