#!/usr/bin/env python3
import sys
import math

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


def main():
    N = int(readline())
    print(math.ceil(N / 2) / N)


if __name__ == '__main__':
    main() import sys sys import math math 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 def main():
    N = int(readline())
    print(math.ceil(N / 2) / N) main N = int(readline()) N int(readline()) int readline() readline print(math.ceil(N / 2) / N) print math.ceil(N / 2) / N math.ceil(N / 2) math.ceil math ceil N / 2 N 2 N if __name__ == '__main__':
    main() __name__ == '__main__' __name__ '__main__' main() main read = sys.stdin.buffer.read sys.stdin.buffer.read read readline = sys.stdin.buffer.readline sys.stdin.buffer.readline readline def main():
    N = int(readline())
    print(math.ceil(N / 2) / N) def main():
    N = int(readline())
    print(math.ceil(N / 2) / N) main readlines = sys.stdin.buffer.readlines sys.stdin.buffer.readlines readlines
#!/usr/bin/env python3
import sys
import math

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


def main():
    N = int(readline())
    print(math.ceil(N / 2) / N)


if __name__ == '__main__':
    main()
