import sys
N = input()
if (N % 2 == 0):
    print N / 2
else:
    print N
sys.exit()    
for i in range(1, 100):
    a = 1
    t1 = 0
    deg = [0] * 10000
    for x in range(i):
        t1 += a
        a += 1
    for x in range(1, t1 / 2 + 1):
        if (t1 % x == 0):
            deg[x] += 1
    a = 2
    t2 = 0
    for x in range(i):
        t2 += a
        a += 1
    for x in range(1, t2 / 2 + 1):
        if (t2 % x == 0):
            deg[x] += 1
    res = 0
    for index,x in enumerate(deg):
        if (x >= 2):
            res = max(res, index)
    print i,res