n = int(input())
dp = [i for i in range(n+1)]
dp[1] = 0

for i in range(2,n+1):
    k = 2
    for k in range(2,n+1):
        if i*k > n:
            break
        dp[i*k] = min(dp[i*k],dp[i]+k)

print(dp[n])