Problem:
Score : 100 points

Problem Statement

Given is an integer N.

Takahashi chooses an integer a from the positive integers not greater than N with equal probability.

Find the probability that a is odd.

Constraints

1 \leq N \leq 100

Input

Input is given from Standard Input in the following format:

N

Output

Print the probability that a is odd.
Your output will be considered correct when its absolute or relative error from the judge's output is at most 10^{-6}.

Sample Input 1

4

Sample Output 1

0.5000000000

There are four positive integers not greater than 4: 1, 2, 3, and 4. Among them, we have two odd numbers: 1 and 3. Thus, the answer is \frac{2}{4} = 0.5.

Sample Input 2

5

Sample Output 2

0.6000000000

Sample Input 3

1

Sample Output 3

1.0000000000

Solution in Python (3.4.3) (judge verdict: Runtime Error)

a,b=[int(x) for x in input().split()]
i=1
def gcd(a,b):
  a,b=max(a,b),min(a,b)
  if a%b==0:
    return b
  else:
    return gcd(b,a%b)
g=gcd(a,b)
l=[]
while(i*i<=g):
    if g%i==0 and i*i!=g:
        l.append(i)
        l.append(g//i)
    if i*i==g:
        l.append(i)
    i=i+1
l=sorted(l)
i=1
while(i<len(l)):
    if l[i]!=0:
        j=i+1
        while(j<len(l)):
            if l[j]%l[i]==0:
                l[j] = 0
            j=j+1
    i=i+1
l=list(filter ( lambda x:x!=0,l))
print(len(l))