Problem:
 Score : 100 points    Problem Statement Find the number of ways to choose a pair of an even number and an odd number from the positive integers between 1 and K (inclusive). The order does not matter.      Constraints  2\leq K\leq 100  K is an integer.         Input Input is given from Standard Input in the following format:  K       Output Print the number of ways to choose a pair of an even number and an odd number from the positive integers between 1 and K (inclusive).        Sample Input 1 3      Sample Output 1 2  Two pairs can be chosen: (2,1) and (2,3) .       Sample Input 2 6      Sample Output 2 9       Sample Input 3 11      Sample Output 3 30       Sample Input 4 50      Sample Output 4 625

Solution (Python):
k = int(input())
num_list = []
for num in range(1, k+1):
    if num % 2 != 0:
        for gsu in range(1, k+1):
            if gsu % 2 == 0:
                pair = []
                pair.append(num)
                pair.append(gsu)
                num_list.append(pair)
print(len(num_list))

Solution (Python):
k = int(input())
if k % 2 == 0:
    print((k//2)**2)
else:
    print((k//2)*(k//2+1))

Solution (Python):
k = input()
even = k/2
odd = k - k/2
print even * odd

Solution (Python):
a=int(input())
print(a//2*(a-a//2))

Solution (Python):
k = int(input())
if k % 2 == 0:
    ans = int((k/2) ** 2)
else:
    ans = int((k // 2) * (k // 2 + 1))
print(ans)

Solution (Python):
a=int(input());print((a//2)*((a+1)//2))

Solution (Python):
A=int(input())
if A%2==0 :
  print(int((A/2)**2))
else :
  print(int(int(A/2)*(int(A/2)+1)))

Solution (Python):
K=int(input())
print(int((K//2)*((K+1)//2)))

Solution (Python):

from collections import defaultdict
from collections import deque
from heapq import heappush, heappop
import sys
import math
import bisect
import random
import itertools
sys.setrecursionlimit(10**5)
stdin = sys.stdin
def LI(): return list(map(int, stdin.readline().split()))
def LF(): return list(map(float, stdin.readline().split()))
def LI_(): return list(map(lambda x: int(x)-1, stdin.readline().split()))
def II(): return int(stdin.readline())
def IF(): return float(stdin.readline())
def LS(): return list(map(list, stdin.readline().split()))
def S(): return list(stdin.readline().rstrip())
def IR(n): return [II() for _ in range(n)]
def LIR(n): return [LI() for _ in range(n)]
def FR(n): return [IF() for _ in range(n)]
def LFR(n): return [LI() for _ in range(n)]
def LIR_(n): return [LI_() for _ in range(n)]
def SR(n): return [S() for _ in range(n)]
def LSR(n): return [LS() for _ in range(n)]
mod = 1000000007


def A():
    n = II()
    ans = n * 800
    print(ans-(n//15)*200)
    return


def B():
    k = II()
    a = k // 2
    b = (k + 1) // 2
    print(a*b)
    return


def C():
    return


def D():
    return


def E():
    return


def F():
    return


def G():
    return


def H():
    return


if __name__ == '__main__':
    B()

Solution (Python):

from collections import defaultdict
from collections import deque
from heapq import heappush, heappop
import sys
import math
import bisect
import random
def LI(): return list(map(int, sys.stdin.readline().split()))
def I(): return int(sys.stdin.readline())
def LS():return list(map(list, sys.stdin.readline().split()))
def S(): return list(sys.stdin.readline())[:-1]
def IR(n):
    l = [None for i in range(n)]
    for i in range(n):l[i] = I()
    return l
def LIR(n):
    l = [None for i in range(n)]
    for i in range(n):l[i] = LI()
    return l
def SR(n):
    l = [None for i in range(n)]
    for i in range(n):l[i] = S()
    return l
def LSR(n):
    l = [None for i in range(n)]
    for i in range(n):l[i] = SR()
    return l
mod = 1000000007


def A():
    n = I()
    print(n*800-200*(n//15))


def B():
    k = I()
    ans = 0
    for i in range(1,k):
        for j in range(i+1,k+1):
            if (i%2)^(j%2):
                ans += 1
    print(ans)


def C():
    return


def D():
    return


def E():
    return


def F():
    return


def G():
    return


def H():
    return

def J():
    return

def K():
    return


if __name__ == "__main__":
    B()

Solution (Python):
K=int(input())
if (K%2)==0:
    f=int(K/2)
    t=f
else:
    f=int((K-1)/2)
    t=f+1
print(str(t*f))

Solution (Python):
N = int(input())
print((N//2) * ((N+1)//2))

Solution (Python):
k=int(input())
if k%2==0:
    print((k//2)**2)
else:
    a=k//2
    print(a*(k-a))

Solution (Python):
n=int(input())
if n%2==0:
  print(int(n/2)**2)
else:
  print(int(n//2*(n//2+1)))

Solution (Python):
k = int(input())
if(k%2==0):
    print(int((k/2)**2))
else:
    print(int((k**2-1)/4))

Solution (Python):
K = int(input())

if K % 2 == 0:
  k = round(K / 2)
  print(k * k)

if K % 2 == 1:
  k = round(K / 2)
  print((k - 1) * k)

Solution (Python):
a = int(input())
if a%2==0:
  print(int((a/2)**2))
else:
  print(int(((a-1)/2)*((a+1)/2)))

Solution (Python):
import math
K = int(input())
print(int(K/2)*math.ceil(K/2))

Solution (Python):
k=int(input())
ise=k%2==0
if ise:
  ne=k/2
  no=k/2
else:
  ne=(k-1)/2
  no=(k+1)/2
print(int(ne*no))

Solution (Python):
K = int(input())
even,odd=0,0
if K%2==1:
    even,odd=K//2,(K//2)+1
else:
    even,odd=K//2,K//2
print(even*odd)

Solution (Python):
K=int(input())
if K%2==0:
    print((K//2)**2)
else:
    print((K//2)*(K//2+1))

Solution (Python):
K = int(input())
if(K%2 == 0):
  a = K//2
  print(a*a)
else:
  a = K//2 + 1
  print(a*(a-1))

Solution (Python):
k = int(input())
print(k//2*(k//2+k%2))

Solution (Python):
k = int(input())
print((k // 2) * ((k + 1) // 2))

Solution (Python):
K = int(input())
print((K - int(K / 2)) * int(K / 2))

Solution (Python):
n=int(input())
if n%2==0:
    print(int((n//2)**2))
else:
    print(int(n//2)*(n//2+1))

Solution (Python):
n = int(input())

if n % 2 == 0:
  print((n//2)**2)
else:
  print((n//2)*(n//2+1))

Solution (Python):
K=int(input())
print(K//2*(K-K//2))

Solution (Python):
k = int(input())

print( int( (k//2) * int(k/2+0.5) ))

Solution (Python):
K = int(input())

num_even = K // 2
num_odd = (K + 1) // 2

print(num_even * num_odd)

Solution (Python):

N = int(input())
print([(N // 2) * (N // 2 + 1), (N // 2) ** 2][N % 2 == 0])

Solution (Python):
K = int(input())
print((K+1)//2*(K//2))

Solution (Python):
K = int(input())
if K%2 == 0:
    print(int((K//2)**2))
else:
    print(int((K//2+1)*(K//2)))

Solution (Python):
K = int(input())
print((K//2) * ((K+1)//2))

Solution (Python):
K = int(input())
Q, R = divmod(K, 2)
print(Q * (Q + R))

Solution (Python):
K = int(input())
evens = K >> 1
odds = evens + (K & 1)
print(evens * odds)

Solution (Python):
k=int(input())
if k%2==0:
	print(int(k*k/4))
else:
	print(int(((k-1)/2)*((k+1)/2)))

Solution (Python):
k=int(input())
print((k//2)*((k//2)+(k%2)))

Solution (Python):
K = int(input())
if K % 2:
  odd = (K + 1) // 2
  even = K // 2
else:
  odd = K // 2
  even = K // 2
print(odd * even)

Solution (Python):
K = int(input())

if(K%2==0):
    even_count = int(K/2)
    odd_count = int(K/2)
else:
    even_count = int(K/2)
    odd_count = int(K/2)+1

print(even_count * odd_count)

Solution (Python):
K = int(input())
a = K//2
b = K-a
print(a*b)

Solution (Python):
K=int(input())
print((K//2)*(K//2+K%2))

Solution (Python):
ri = lambda: int(input())
rl = lambda: list(map(int,input().split()))
rr = lambda N: [ri() for _ in range(N)]
YN = lambda b: print('YES') if b else print('NO')
yn = lambda b: print('Yes') if b else print('No')
OE = lambda x: print('Odd') if x%2 else print('Even')
INF = 10**18

K=ri()
print(K//2 * (K-K//2))

Solution (Python):
K = int(input())
a = K // 2
b = K - a
print(a * b)

Solution (Python):
K=int(input())
o=(K+1)//2
e=K//2
print(o*e)

Solution (Python):
from sys import stdin
K=int(stdin.readline().rstrip())
lst=list(range(1,K+1))
ans=len(lst[0::2])*len(lst[1::2])
print(ans)

Solution (Python):
k=int(input())
e=[]
o=[]
for i in range(1,k+1):
    if i%2==0:
        e.append(i)
    else:
        o.append(i)
print(len(e)*len(o))

Solution (Python):
a=int(input())
print(a//2*((a+1)//2))

Solution (Python):
K =int(input())
if K%2==0:
  print(K//2*K//2)
else:
  print(K//2*(K//2+1))

Solution (Python):
def pair(K: int)->int:
    even = K // 2
    odd = K // 2 + (0 if K % 2 == 0 else 1)

    return even * odd


if __name__ == "__main__":
    K = int(input())
    ans = pair(K)
    print(ans)

Solution (Python):
K = int(input())
if K % 2 == 0:
    print((K//2)*(K//2))
else:
    print((K//2+1)*(K//2))

Solution (Python):
K = int(input())
print(((K+1)//2)*(K//2))

Solution (Python):
K = int(input())
even = K // 2
odd = (K+1)//2
print(even*odd)

Solution (Python):
K=int(input())
print((K>>1)*(-(-K>>1)))

Solution (Python):
K = int(input())
odd = K // 2 if K % 2 == 0 else K // 2 + 1
even = K // 2
print(odd * even)

Solution (Python):
K = int(input())
if K % 2 == 0:
    print(K * K // 4)
else:
    print((K - 1) * (K + 1) // 4)

Solution (Python):
a=int(input());print(a//2*(a//2+1)if a%2>0else a*a//4)

Solution (Python):
K = int(input())

if K % 2 == 0:
    print(int(K / 2) ** 2)
else:
    print(int((K - 1) / 2) * int((K - 1) / 2 + 1))

Solution (Python):
k = int(input())

c=0

for i in range(1,k+1):
	for j in range(1,k+1):
		if i % 2 ==0:
			if j % 2 == 1:
				c += 1
print(c)

Solution (Python):
k=int(input())
print((k//2)*((k+1)//2))

Solution (Python):
K=int(input())
print((K//2)**2  if K%2==0 else K//2*(K//2+1))

Solution (Python):
K=int(input())
if K%2==0:
  print((K//2)**2)
else:
  print(K//2*(K//2+1))

Solution (Python):
K = int(input())

tmp = K//2
if K % 2==0:
    ans = tmp*tmp
else:
    ans = tmp*(tmp+1)
print(ans)

Solution (Python):
import itertools
K = int(input())
if K%2 == 0:
  A = range(2,K+1,2)
  B = range(1,K,2)
else:
  A = range(2,K,2)
  B = range(1,K+1,2)
print(len(list(itertools.product(A,B))))

Solution (Python):
n=int(input())
print((n//2)*(n-n//2))

Solution (Python):
N=int(input())
print((N//2)**2 if N%2==0 else (N//2)*(N//2+1))

Solution (Python):
K = int(input())

ans = (K // 2) * ((K + 1) // 2)

print(ans)
print()

Solution (Python):
K = int(input())

if K % 2 == 0:
    answer = (K // 2)**2
else:
    answer = (K//2)*(K//2 +1)

print(answer)

Solution (Python):
N = int(input())
print((N//2)*(N-N//2))

Solution (Python):

k = int(input())
print((k // 2) * ((k + 1) // 2))

Solution (Python):
import itertools

K = int(input())

even = [n for n in range(1, K+1) if n % 2 == 0]
odd = [n for n in range(1, K+1) if n % 2 != 0]

ans = list(itertools.product(even, odd))

print(len(ans))

Solution (Python):
k = int(input())
ans = 0
if k%2 == 1:
    n = (k+1)/2
    ans = n * (n-1)
else:
    ans = (k/2)*(k/2)
print(int(ans))

Solution (Python):
k = int(input())
ans = 0
if k%2 == 1:
    n = (k+1)/2
    ans = n * (n-1)
else:
    ans = (k/2)*(k/2)
print(int(ans))

Solution (Python):
n=int(input())
a=n//2
if n%2!=0:
    a+=1
b=n//2
print(a*b)

Solution (Python):
k=int(input())
print((k//2)*((k+1)//2))

Solution (Python):
def main():
    K = int(input())
    odd, even = (K+1)//2, K//2
    print(odd*even)


if __name__ == "__main__":
    main()

Solution (Python):

K=int(input())
print(K//2*(K//2+K%2))

Solution (Python):

K=int(input())
print(K//2*(K//2+K%2))

Solution (Python):
k = int(input())
even = k//2
odd = k-even
print(even*odd)

Solution (Python):
K = int(input())

if K%2 == 0:
    print((K//2)**2)
else:
    print((K//2) * (K//2 +1 ))

Solution (Python):
K=int(input())
if K%2==0:
  print((K//2)**2)
else:
  print(K//2*(K//2+1))

Solution (Python):
k = int(input())
if k%2==0:
  print((int(k/2))**2)
else:
  tmp = int(k/2)
  print(tmp*(tmp+1))

Solution (Python):
K=int(input())
print((K//2)*((K+1)//2))

Solution (Python):
a = int(input())
if a % 2 == 0:
    print(int((a/2)**2))
else:
    print(int((a-1)/2*(a+1)/2))

Solution (Python):
N = int(input())

print((N//2)*(N//2+N%2))

Solution (Python):
K=int(input())
print((K//2)*((K+1)//2))

Solution (Python):
k = int(input())
if k % 2 == 1:
    print((k + 1) * (k - 1) // 4 )
else:
    print((k//2)**2)

Solution (Python):
k=int(input())
print((k//2)**2 if k%2==0 else(k//2)*(k+1)//2)

Solution (Python):
k=int(input())
print((k//2)**2 if k%2==0 else(k//2)*(k+1)//2)

Solution (Python):
k = int(input())
count = 0


def is_even(num):
    return num % 2 == 0


for i in range(1, k + 1):
    for j in range(i, k + 1):
        if (is_even(i) & (not is_even(j))) | (is_even(j) & (not is_even(i))) :
            count += 1

print(count)

Solution (Python):
k=int(input())
e=0
o=0
if k%2==0:
    e=k/2
    o=k/2
else:
    e=(k-1)/2
    o=(k-1)/2+1

print(int(e*o))

Solution (Python):
from sys import stdin

k = int(stdin.readline().rstrip())

print((k//2)*((k+1)//2))

Solution (Python):
def main():
    K = int(input())
    n = K // 2
    if K % 2 == 0:
        print(n * n)
    else:
        print(n * (n+1))


if __name__ == "__main__":
    main()

Solution (Python):
k=int(input());print(k//2*(k-k//2))

Solution (Python):
k = int(input())

if k%2==0 :
    a = k//2
    b = k//2
    print(a*b)

else :
    a = k//2
    b = k//2+1
    print(a*b)

Solution (Python):
k = int(input())

m = k % 2
ro = (k + m) // 2
re = k // 2

print(ro * re)

Solution (Python):
k = int(input())

print(int((k**2)/4) if k%2==0 else int(((k**2)-1)/4))

Solution (Python):
K = int(input())

if K%2 == 0:
	print(int(K**2/4))
else:
	print(int((K-1)/2*((K-1)/2 + 1)))

Solution (Python):


K = int(input())

print((K // 2) * (K // 2 + K % 2))

Solution (Python):
K = int(input())
odd = K // 2
even = K - odd
print(odd * even)

Solution (Python):
k = int(input())
if k%2 == 0:
    print(round(k/2) **2)
else:
    print(round((k+1)/2) * round((k-1)/2))

Solution (Python):


import math
import sys
import heapq
from operator import itemgetter
import itertools
input = sys.stdin.readline











n = int(input().rstrip())
if n % 2 == 0:
	print((n//2)**2)
else:
	print(n//2 * (n//2 + 1))

Solution (Python):
k = int(input())
print(int(k/2) * (int(k/2) + k%2))

Solution (Python):
K = int(input())
if K % 2 == 0:
	print(int((K / 2) ** 2))
else:
	print(int((K ** 2 - 1) / 4))

Solution (Python):
k = int(input())
if k % 2 == 0:
    print(k * k // 4)
else:
    print((k ** 2 - 1) // 4)

Solution (Python):
print input()**2/4

Solution (Python):
print(int(input())**2//4)

Solution (Python):
K=int(input())
if K%2==0:
  print(int((K/2)**2))
else:
  print(int((K-1)/2*(K+1)/2))

Solution (Python):
N = int(input())
print((N // 2) * (N - N // 2))

Solution (Python):
def main() -> None:
    N = int(input())
    a = N // 2
    b = N // 2 + N % 2
    print(a * b)


if __name__ == '__main__':
    main()

Solution (Python):
int_k = int(input())

if int_k % 2 == 0:
    print((int_k // 2) ** 2)
else:
    print((int_k // 2) * ((int_k //2) + 1))

Solution (Python):
K = int(input())

flg = False
p = 0
count = 0
for i in range(K-1):
    if flg:
        count += p
    else:
        p += 1
        count += p
    flg = not flg

print(count)

Solution (Python):
K = int(input())
odd = (K + 1) // 2
even = K // 2
print(odd * even)

Solution (Python):
k = raw_input()
k = int(k)
c = 0
for i in range(2,k+1,2):
	for j in range(1,k+1,2):
			c += 1
print(c)

Solution (Python):
k = int(input())
if k % 2 == 0:
  	print(int((k / 2)**2))
else:
	print(int(k//2 * (k//2 + k%2)))

Solution (Python):
k = int(input())
print(int(k*k/4))

Solution (Python):
K = int(input())
print((K // 2) * (-(-K // 2)))

Solution (Python):
k = int(input())
if k % 2 == 0:
  print(int(k**2/4))
else:
  print(int((k+1)*(k-1)/4))

Solution (Python):
import sys

def main():
  input = sys.stdin.readline
  N = int(input())
  print(N//2 * (N//2 + N%2))


if __name__ == '__main__':
  main()

Solution (Python):
k = int(input())
if k % 2 == 0:
    print(int((k /2) ** 2))
else :
    print(int((k // 2) * (k // 2 + 1)))

Solution (Python):
k = int(input())

even_number = list(range(2,k+1,2))
odd_number = list(range(1,k+1,2))


print(len(even_number)*len(odd_number))

Solution (Python):
k = int(input())

if k%2 == 0:
    print((k//2)*(k//2))
elif k%2 == 1:
    print((k//2)*(k//2+1))

Solution (Python):
k=int(input())
if k%2==0:
    print((k//2)**2)
else:
    print((k//2+1)*(k//2))

Solution (Python):
k = int(input())

if k % 2 == 0:
    print((k//2)**2)
else:
    a = k//2
    b = a + 1
    print(a * b)

Solution (Python):
K = int(input())

print((K//2)*((K+1)//2))

Solution (Python):
N = int(input())
print(N//2 *(N-N//2))

Solution (Python):
k = int(input())
e = k//2
o = k - e
print(o*e)

Solution (Python):
k = int(input())
o = k//2 + k%2
e = k//2
print(o*e)

Solution (Python):
k = int(input())
if k % 2 == 1:
    ans = (k//2)*(k//2+1)
else:
    ans = (k//2)*(k//2)
print(ans)

Solution (Python):
k = int(input())

if k % 2 == 0:
    print(round((k/2)*(k/2)))
else:
    print(int(k/2)*int(k/2+1))

Solution (Python):
import numpy as np


def num_even_odd(num):
    num_odd = np.ceil(num/2)
    num_even = num//2
    return num_odd, num_even


def main(num):
    odds, evens = num_even_odd(num)
    print(int(odds * evens))


if __name__ == "__main__":
    main(int(input()))

Solution (Python):
print(int(input())**2>>2)

Solution (Python):
a = int(input())
if a%2 == 0:
    print(int((a/2)*(a/2)))
else:
    print(int(a/2)*int(a/2+1))

Solution (Python):
k = int(input())

if k % 2 == 0:
    print(int(k/2*k/2))
else:
    print(int((k-1)/2*(k-1)/2 + (k-1)/2))

Solution (Python):
k = int(input())
print((k//2)*((k+1)//2))

Solution (Python):
K = int(input())
print((K//2)*((K+1)//2))

Solution (Python):
k = int(input())
if k % 2 == 0:
    m = k//2
    ans = m**2
    print(ans)
else:
    m = (k+1)//2
    l = (k-1)//2
    ans = m*l
    print(ans)

Solution (Python):
k = int(input())
print((k // 2 * k // 2) if (k % 2 == 0) else ((k // 2) * (k // 2 + 1)))

Solution (Python):
n = int(input())
a = n // 2
b= n-a
print(a*b)

Solution (Python):
k = int(input())
if k%2 == 1:print((k//2)*(k//2+1))
else: print((k//2)*(k//2))

Solution (Python):
K=int(input())

if K%2:
    print(int(K**2/4-0.25))
else:
    print(int((K/2)**2))

Solution (Python):
import itertools
N= int(input())
kisou = []
gusou = []
for num in [i for i in range(N+1)][1:]:
    if num%2==0:
        gusou.append(num)
    else:
        kisou.append(num)
print(len(list(itertools.product(kisou, gusou))))

Solution (Python):
K = int(input())
count = 0
for i in range(1, K+1, 2):
    for j in range(2, K+1, 2):
        count += 1
print(count)

Solution (Python):
k = int(input())
res = int(k/2);
if k % 2 == 0 :
	print(int(res*res))
else:
	print(int((res+1)*res))

Solution (Python):
import math
k=int(input())
odd=math.ceil(k/2)
even=k//2
print(odd*even)

Solution (Python):
N=int(input())
A=int(N/2)
B=N%2
C=int(A*(A+B))
print(C)

Solution (Python):
K = int(input())
if K%2 == 1:
  print(int((K-1)/2 * (K+1)/2))
else:
  print(int((K/2)**2))

Solution (Python):
from collections import defaultdict
K = int(input())
d = defaultdict(lambda: 0)
for i in range(1, K + 1):
    d[i % 2] += 1
print(d[0] * d[1])

Solution (Python):
K=int(input())
print((K//2)*((K + 2 - 1) // 2))

Solution (Python):
a=int(input())
if a%2==1:
    ans=a//2*(a//2+1)
else:
    ans=a//2*a//2
print(ans)

Solution (Python):
K = int(input())

if K % 2 == 0:
  print(K ** 2 // 4)
else:
  print(K // 2 * (K + 1) // 2)

Solution (Python):
k = int(input())
even = 0
odd = 0
for i in range(1, k+1):
    if i % 2 == 0:
        even += 1
    else:
        odd += 1
print(even * odd)

Solution (Python):


def main():
    K = int(input())


    print(int((K + 1) / 2) * int(K / 2))


if __name__ == '__main__':
    main()

Solution (Python):
"""AtCoder"""

import sys
input = sys.stdin.readline

N = int(input())

if N % 2 == 0:
    print(int(N/2)*int(N/2))
else:
    print(int(N/2)*int(N/2+1))

Solution (Python):
def main():
    K = int(input())
    print((K // 2) * (K - K // 2))


main()

Solution (Python):
n = int(input())
print(int((n // 2) * (n // 2 + 1) if n % 2 else n * n / 4))

Solution (Python):
K =int(input())
a =K//2
b =K-a
print(a*b)

Solution (Python):
k=int(input())
if(k%2==0):
    print(int((k/2)**2))
else:
    j=int(k/2)
    print(j*(j+1))

Solution (Python):

import math
K = int(input())

print( math.floor(K/2.0) * math.ceil(K/2.0) )

Solution (Python):
def main():
    k = int(input())
    if k % 2 == 0:
        print(int((k / 2) ** 2))
    else:
        print(int(k // 2 * (k // 2 + 1)))


if __name__ == '__main__':
    main()

Solution (Python):
K = int(input())
if K % 2 == 0: print((K//2)**2)
else: print(((K//2+1)*(K//2)))

Solution (Python):
K=int(input())
A=int(K/2)
if K%2 == 0:
    ans=A*A
else:
    ans=(A+1)*A
print(ans)

Solution (Python):
K = int(input())

n1 = K//2
n2 = (K+1)//2

print(n1*n2)

Solution (Python):
k = int(input())
n2 = k // 2
n1 = k - n2
print(n1 * n2)

Solution (Python):
k = int(input())
print((k//2)*((k+1)//2))

Solution (Python):
K=int(input())
A=K%2
if A==0:
    print(int(K*K/4))
else:
    print(int((K*K-1)/4))

Solution (Python):
k = int(input())
print( k//2 * (k-k//2))

Solution (Python):
K = int(input())
print(int(K / 2) ** 2 if K % 2 == 0 else (K // 2) * (K // 2 + 1))

Solution (Python):
k=int(input())
print(((k-1)//2)*((k-1)//2+1) if k%2==1 else (k**2)//4)

Solution (Python):
K = int(input())
if(K % 2 == 0):
  print(int(K/2)**2)
else:
  ceil = int((K + 1)/2)
  print(ceil**2 - ceil)

Solution (Python):
c = 0
l = 0
n = int(input())
for i in range(1, n + 1):
    if i % 2 == 0:
        c += 1
    else:
        l += 1
print(c * l)

Solution (Python):
n = int(input())


if n % 2 == 0:
    ans = int(n/2)
    n -= 1
    while n > 0:
        ans += int(n/2)
        n -= 1
else :
    ans = 0
    while n > 0:
        ans += int(n/2)
        n -= 1

print(ans)

Solution (Python):

K = int(input())

print((K // 2) * ((K + 1) // 2 ))

Solution (Python):
def main(k):
    print(-(k//2)*(-k//2))

k = int(input())
main(k)

Solution (Python):
K=int(input())
a=K//2
b=-(-K//2)
print(a*b)

Solution (Python):
n = int(input())
if n % 2 == 0:
    print((n//2)**2)
else:
    print((n//2)*(n//2+1))

Solution (Python):
K = int(input())
if K % 2 == 0: print((K//2)**2)
else: print((K-1)//2*(K+1)//2)

Solution (Python):
n = int(input())
if n % 2 == 0:
    print(int((n/2)**2))
else:
    print(int((n//2)*(n//2+1)))

Solution (Python):
K = int(input())
if K % 2 == 0:
    print(K ** 2 // 4)
else:
    print((K - 1) * (K + 1) // 4)

Solution (Python):
k = int(input())
print(int((k/2)**2)) if k%2 == 0 else print(int((k/2)**2 - 1/4))

Solution (Python):
a=int(input())
b=a//2
if a%2==0:
  print(b*b)
else:
  print(b*(b+1))

Solution (Python):
K = int(input())
print((K // 2) * ((K + 1) // 2))

Solution (Python):
k=int(input())
print((k//2)*((k+1)//2))

Solution (Python):
K = int(input())
a = []
b = []
counter = 0

for i in range(K):
    if i % 2 == 0:
        a.append(i)
    else:
        b.append(i)

for p in a:
    for s in b:
        counter += 1

print(counter)

Solution (Python):
N = int(input())
if N % 2 == 0:
    print(int((N/2)**2))
else:
    print(int((N//2) * (N//2 + 1)))

Solution (Python):
K = int(input())

odd = (K + 1) // 2
even = K // 2

print(odd * even)

Solution (Python):
K = int(input())
if K % 2 == 0:
  ans = K/2 * (K - K/2)
else:
  ans = (K-1)/2 * (K - (K-1)/2)
print(int(ans))

Solution (Python):
K = int(input())
if K%2 :
    print((K//2)*((K//2)+1))
else:
    print(int((K/2)**2))

Solution (Python):
K = int(input())
print((K// 2)*((K+1)//2))

Solution (Python):
K = int(input())
if K % 2 == 0:
    print((K // 2) ** 2)
else:
    print((K // 2)* ((K // 2) + 1))

Solution (Python):
k = int(input())
if k % 2 == 0:
    print((k//2) * (k//2))
else:
    print(((k+1)//2) * (k//2))

Solution (Python):
k = int(input())
print((k // 2) * (k // 2 + k % 2))

Solution (Python):
k = int(input())
print((k//2) * (k//2 + k%2))

Solution (Python):
n = int(input())
print((n-n//2)*(n//2))

Solution (Python):
def main():
    k = int(input())
    if k % 2 == 0:
        print((k // 2) ** 2)
    else:
        print((k // 2) * (k + 1) // 2)


if __name__ == '__main__':
    main()

Solution (Python):
k = int(input())

print((int(k) // 2) * ((int(k) + 1) // 2))

Solution (Python):
k=int(input())
if k%2==0:
    print((k//2)**2)
else:
    print((k//2+1)*(k//2))

Solution (Python):
K = int(input())
print( K ** 2 // 4) if K % 2 == 0 else print(((K-1)*(K+1)//4))

Solution (Python):
k = int(input())

if(k%2==0):
    even = k/2
    odd = k/2
else:
    even = (k-1)/2
    odd = k-even

print(int(even*odd))

Solution (Python):
K = int(input())

A = int(K / 2)
B = int(K - A)

print(A * B)

Solution (Python):
K = int(input())

if K % 2 == 1:
   print((K//2) * (K//2 +1)) 

else:
    print((K//2)**2)

Solution (Python):
a = int(input())
if a % 2 == 0:
    print((a//2) * (a//2))
else:
    print((a//2+1) * (a//2))

Solution (Python):
K = int(input())

print((K//2) * ((K+1)//2))

Solution (Python):
K = int(input())

odd = (K + 1) // 2
even = K // 2

print(odd * even)

Solution (Python):
a = int(input())
if a%2==0:
    a = ((a/2)**2)
else:
    a = ((a//2)*((a//2)+1))
print(int(a))

Solution (Python):
a = int(input())
if a % 2 == 0:
  print((a // 2) * (a // 2))
else:
  print((a // 2 + 1) * (a // 2))

Solution (Python):
n=int(input())
if n % 2==0:
	print((n//2)**2)
else:
	m=(n+1)//2
	print(m*(n-m))

Solution (Python):
N = int(input())
odd = N % 2 + N // 2
even = N // 2
print(odd*even)

Solution (Python):
k = int(input())

if k%2 == 0:
    print(k//2 * k//2)
else:
    print(k//2 * (k//2 + 1))

Solution (Python):
k = int(input())
if k%2==0:
    print(int(k**2/4))
else:
    print(int((k**2-1)/4))

Solution (Python):
K = int(input())
print((K // 2) ** 2 if K % 2 == 0 else ((K + 1) // 2 ) * ((K - 1) // 2))

Solution (Python):
k = int(input())
cnt = 0
for i in range(1, k + 1):
    for j in range(1, k + 1):
        if i % 2 != j % 2:
            cnt += 1
print(cnt // 2)

Solution (Python):
K=int(input())
if K%2==0:
  print((K**2)//4)
else:
  print((K//2)*(K//2+1))

Solution (Python):
a=int(input())
print((a//2)*((a+1)//2))

Solution (Python):
k = int(input())
if k % 2 == 0:
	print(k // 2 * k // 2)
else:
	print(k // 2 * (k // 2 + 1))

Solution (Python):
K = int(input())
print((K//2)*(K-(K//2)))

Solution (Python):
K = int(input())
print((K // 2) * ((K+1) // 2))

Solution (Python):

K=int(input())

print((K//2)*(K-(K//2)))

Solution (Python):
n = int(input())
a = n//2
b = n - a
print(a*b)

Solution (Python):
k = int(input())
e = k // 2
o = k // 2 if k % 2 == 0 else k // 2 + 1
print(e * o)

Solution (Python):
k = int(input())
count = 0
for i in range(1,k):
    if (k-i) % 2 == 0:
        count += (k-i) // 2
    else:
        count += (k-i) // 2 + 1

print(count)

Solution (Python):

K = int(input())
if K % 2 == 0:
  print((K//2)*(K//2))
elif K % 2 == 1:
  print(((K+1)//2)*((K-1)//2))

Solution (Python):



def main():
    """Function."""
    k = int(input())
    if k % 2 == 0:
        print((k//2)**2)
    else:
        print(((k//2)+1)*(k//2))


if __name__ == "__main__":
    main()

Solution (Python):
K = int(input())
gu = []
ki = []
for i in range(1,K+1):
    if i%2 == 0:
        gu.append(i)
    else:
        ki.append(i)

print(len(gu)*len(ki))

Solution (Python):
k = int(input())
 
even = k // 2
odd = (k + 1) // 2 
 
print(even * odd)

Solution (Python):
k = int(input())

even = k // 2
odd = k // 2

if k % 2 != 0:
  odd = odd + 1
  
print(even * odd)

Solution (Python):
k=int(input())
print((k//2)*((k+1)//2))

Solution (Python):
k = int(input())

even = k//2
odd  = k//2

if k%2 != 0:
    odd = even+1

print(even*odd)

Solution (Python):
n=int(input())
if n%2==0:
  print(int((n/2)*(n/2)))
else:
  print(int(-(-n//2))*(n//2))

Solution (Python):
k = int(input())
print((k // 2) * ((k+1) // 2))

Solution (Python):
K = int(input())
print(int(K/2)*int((K+1)/2))

Solution (Python):
k = int(input())
l = k //2
if k % 2 == 0:
  print(l**2)
else:
  print(l * (l + 1))

Solution (Python):
n=int(input())
count=0
for i in range(1,n+1,2):
  for j in range(2,n+1,2):
    count+=1
print(count)

Solution (Python):

K = int(input())

print(K // 2 * (K // 2 + K % 2))

Solution (Python):
K = int(input())
if K % 2 == 0:
  ans = (K // 2)**2
elif K % 2 == 1:
  a = K // 2
  b = a + 1
  ans = a * b
print(ans)

Solution (Python):
K = int(input())
if K % 2 == 1:
  ans = int(K / 2) * int(K / 2 + 1)
else:
  ans = int(K / 2) * int(K / 2)
print(ans)

Solution (Python):

k=int(input())
z=k**2//4
print(z)

Solution (Python):
n=int(input())
count=0
for i in range(1,n+1,2):
  for j in range(2,n+1,2):
    count+=1
print(count)

Solution (Python):

n=int(input())
count=0;
for i in range(1,n+1,2):
  for j in range(2,n+1,2):
    count+=1
print(count)

Solution (Python):
K = int(input())
count = 0

for i in range(1, K+1):
    if(i % 2 == 0):
        for j in range(1, K+1):
            if(j % 2 == 1):
                count += 1

print(count)

Solution (Python):
K = int(input())
if K % 2 == 0:
    print(K//2 * K//2)
else:
    print(K//2 * (K//2 + 1))

Solution (Python):
K = int(input())
print((K//2) * (K-K//2))

Solution (Python):
n=int(input());a=n//2;print((n-a)*(a))

Solution (Python):
K = int(input())
print(int(K / 2) * int((K + 1) / 2))

Solution (Python):
k = int(input())
print(int(k//2)*((k+1)//2))

Solution (Python):
k = int(input())
if k % 2 == 0:
    print(int((k/2)**2))
else:
    print(int(k//2)*(k//2+1))

Solution (Python):
n=int(input())
even=[]
odd=[]
for i in range (1,n+1,1):
    if i%2==0:
        even.append(i)
    else:
        odd.append(i)
result=[(x,y) for x in even for y in odd]
print(len(result))

Solution (Python):
N = int(input())
Even = []
Odd = []
for i in range(1,N+1):
    if i % 2 == 0:
        Even.append(i)
    else:
        Odd.append(i)
print(len(Even) * len(Odd))

Solution (Python):
k=int(input())
if k%2==0:
  print(int(k*k/4))
else:
  print(int((k**2-1)/4))

Solution (Python):
N = int(input())
cnt = 0

for i in range(1,N+1):
    for j in range(i+1,N+1):
        if (i + j) % 2 != 0:
            cnt = cnt + 1

print(cnt)

Solution (Python):
K = int(input())

even = K // 2
odd = K - even

print(even * odd)

Solution (Python):
k = int(input())
ans = 0
for i in range(1, k):
    for j in range(i+1, k+1, 2):
        ans += 1
print(ans)

Solution (Python):
y = int(input())

def former (x):
    if x%2 == 0 :
        return int (x/2)**2
    else:
        return int (x/2) * (int(x/2) + 1)

z = former(y)
print (z)

Solution (Python):
K = int(input())

def solve(x):
    if x%2 == 0:
        return int(x / 2) ** 2
    else:
        return int(x / 2) * (int(x / 2) + 1)

ans = solve(K)
print(ans)

Solution (Python):
def main():
    k = int(input())
    print((k // 2) * ((k+1) // 2))

if __name__ == "__main__":
    main()

Solution (Python):
N = int(input())
if N % 2 == 0:
    print((N//2)**2)
else:
    print((N//2) * (N//2+1))

Solution (Python):

def solve():
    i = int(input())

    if i % 2 == 0:
        print((i // 2) ** 2)
    else:
        print((i // 2) * (i // 2 + 1))


if __name__ == '__main__':
    solve()

Solution (Python):
K=int(input())

c=K%2

if(c==0):
    print(int((K/2)*(K/2)))
else:
    print(int(K/2)*(int(K/2)+1))

Solution (Python):
n=(int)(input())
if n%2==0:
    print((n//2)**2)
else:
    print((n//2)*(n//2+1))

Solution (Python):
val1=int(input())
if val1%2==0:
    print((val1//2)*(val1//2))
else:
    val1=val1+1
    print(((val1//2)*(val1//2))-(val1//2))

Solution (Python):
val1=int(input())
if val1%2==0:
    print((val1//2)*(val1//2))
else:
    val1=val1+1
    print(((val1//2)*(val1//2))-(val1//2))

Solution (Python):
n = int(input())
if n&1==0:
    print((n//2)**2)
else:
    print((n//2)*(n//2+1))

Solution (Python):
a = int(input())
b = int(a/2)

print(b*(a-b))

Solution (Python):
N=int(input())
print((N//2)*(N-N//2))

Solution (Python):
N = int(input())
if N%2 == 0:
  print(int((N/2)*(N/2)))
else:
  M = N+1
  print(int((M/2)*(M/2-1)))

Solution (Python):
K = int(input())

print(((K + 1) // 2) * (K // 2))

Solution (Python):
K = int(input())

if K % 2:
    print((int(K / 2) + 1) * int(K / 2))
else:
    print(int((K/2)*K/2))

Solution (Python):
K = int(input())
 
if K % 2 == 0:
  answer = (K / 2)**2
else:
  answer = ((K + 1) / 2)**2 - ((K + 1) / 2)
 
print(int(answer))