n = int(input())
if n%2 == 0:
    print(1/2)
else :
    print((n//2+1)/n) n = int(input()) n int(input()) int input() input if n%2 == 0:
    print(1/2)
else :
    print((n//2+1)/n) n%2 == 0 n%2 n 2 0 print(1/2) print 1/2 1 2 print((n//2+1)/n) print (n//2+1)/n n//2+1 n//2 n 2 1 n n = int(input()) int(input()) n
n = int(input())
if n%2 == 0:
    print(1/2)
else :
    print((n//2+1)/n)
