n = int(input())
INF =10**18
dp = [INF]*(n+1)
dp[1] = 0
for i in range(1, n):
    k = 2
    j = k*i
    while j <= n:
        dp[j] = min(dp[j], dp[i]+k)
        k += 1
        j = k*i
print(dp[n])