i = int(input())
list = []

if i % 2 == 0:
    for m in range(2, int((i+2)/2) + 1):
        if i % m == 0:
            list.append(m + i / m)

if i % 2 == 1:
    for m in range(1, int((i+1)/2), 2):
        if i % m == 0:
            list.append(m + i / m)


list.sort()
print(int(list[0]-2))
