import sys

def I(): return int(sys.stdin.readline().rstrip())

N = I()

print(((N+1)//2)/N) import sys sys def I(): return int(sys.stdin.readline().rstrip()) I N = I() N I() I print(((N+1)//2)/N) print ((N+1)//2)/N (N+1)//2 N+1 N 1 2 N def I(): return int(sys.stdin.readline().rstrip()) def I(): return int(sys.stdin.readline().rstrip()) I N = I() I() N
import sys

def I(): return int(sys.stdin.readline().rstrip())

N = I()

print(((N+1)//2)/N)