#!/usr/bin/env python3

import sys

read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

N = int(read())

odd = 0
for n in range(N):
    n += 1
    if n%2==1:
        odd += 1

print(odd/N) import sys sys read = sys.stdin.buffer.read read sys.stdin.buffer.read sys.stdin.buffer sys.stdin sys stdin buffer read readline = sys.stdin.buffer.readline readline sys.stdin.buffer.readline sys.stdin.buffer sys.stdin sys stdin buffer readline readlines = sys.stdin.buffer.readlines readlines sys.stdin.buffer.readlines sys.stdin.buffer sys.stdin sys stdin buffer readlines N = int(read()) N int(read()) int read() read odd = 0 odd 0 for n in range(N):
    n += 1
    if n%2==1:
        odd += 1 n range(N) range N n += 1 n 1 if n%2==1:
        odd += 1 n%2==1 n%2 n 2 1 odd += 1 odd 1 print(odd/N) print odd/N odd N readline = sys.stdin.buffer.readline sys.stdin.buffer.readline readline readlines = sys.stdin.buffer.readlines sys.stdin.buffer.readlines readlines read = sys.stdin.buffer.read sys.stdin.buffer.read read odd = 0 0 odd odd += 1 1 odd n += 1 1 n N = int(read()) int(read()) N
#!/usr/bin/env python3

import sys

read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

N = int(read())

odd = 0
for n in range(N):
    n += 1
    if n%2==1:
        odd += 1

print(odd/N)