#!/usr/bin/env pypy3

from pprint import pprint
from string import ascii_lowercase as letter
from sys import setrecursionlimit, stdin
from typing import Dict, Iterable, Set

INF: int = 1 << 62
MOD1000000007 = 10**9 + 7
MOD998244353 = 998244353
setrecursionlimit(500_000)
readline = stdin.readline
input = lambda: stdin.readline().rstrip('\r\n')


def inputs(type_=int):
    ins = input().split()

    if isinstance(type_, Iterable):
        return [t(x) for t, x in zip(type_, ins)]
    else:
        return list(map(type_, ins))


def input_(type_=int):
    a, = inputs(type_)
    return a


def input1() -> int:
    return int(readline())


inputi = input1


def input2():
    a = readline().split()
    assert len(a) == 2
    a[0] = int(a[0])
    a[1] = int(a[1])
    return a


def input3():
    a = readline().split()
    assert len(a) == 3
    a[0] = int(a[0])
    a[1] = int(a[1])
    a[2] = int(a[2])
    return a


def input4():
    a = readline().split()
    assert len(a) == 4
    a[0] = int(a[0])
    a[1] = int(a[1])
    a[2] = int(a[2])
    a[3] = int(a[3])
    return a


# start coding

n, k = input2()
print(n / 2)