def prime_factors(n):
    i = 2
    factors = 1
    while i * i <= n:
        if n % i:
            i += 1
        else:
            n //= i
            factors = i
    if n > 1:
        factors = i
    return factors
N = int(input())
large_factor = prime_factors(N)
print(int(large_factor+(N/large_factor)-2))