N = int(input())

def divisor(n):
    i = 1
    table = []
    while i * i <= n:
        if n%i == 0:
            table.append(i)
            table.append(n//i)
        i += 1
    table = list(set(table))
    return table
 
if len(divisor(N)) < 3:
    print(N - 1)
else:
    divisor_list = divisor(N)
    tmp = N
    for i in divisor_list:
        A = i
        B = N / i
        if tmp > (A + B - 2):
            tmp = (A + B - 2)
    print(int(tmp))
