N=int(input())

OK=N
NG=1

while OK>NG+1:
    mid=(OK+NG)//2

    if abs(N/mid - N/(mid+1))<=1:
        OK=mid
    else:
        NG=mid

OK2=N
NG2=1

while OK2>NG2+1:
    mid=(OK2+NG2)//2

    if abs(N/mid - N/(mid+1))<1:
        OK2=mid
    else:
        NG2=mid

ANS=OK+N//OK2

SET=set()

if OK==OK2:
    print(N//OK+OK-1)
else:
    for i in range(OK,OK2):
        x=N//i

        if N//OK2<x<N//OK:
            SET.add(x)

    print(ANS+len(SET))