n = int(input())
ans = n

for i in range(2,min(n+1,10**6+5)):
    x = 0
    num = 1
    while num <= n:
        num *= i
        x += 1
    num //= i
    x -= 1
    ans = min(ans,i+x+n-num)

l = 1
r = n
while r > l+1:
    m = (r+l)//2
    if m**2 > n:
        r = m
    else:
        l = m

ans = min(ans,l+2+n-l**2)
print(ans)