#!/usr/bin/env python3
#!/usr/bin/env python3
N = int(input())
print(0.5 if N % 2 == 0 else ((N//2)+1) / N) N = int(input()) N int(input()) int input() input print(0.5 if N % 2 == 0 else ((N//2)+1) / N) print 0.5 if N % 2 == 0 else ((N//2)+1) / N N % 2 == 0 N % 2 N 2 0 0.5 ((N//2)+1) / N (N//2)+1 N//2 N 2 1 N N = int(input()) int(input()) N
#!/usr/bin/env python3
#!/usr/bin/env python3
N = int(input())
print(0.5 if N % 2 == 0 else ((N//2)+1) / N)
