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):
import sys, re
from collections import deque, defaultdict, Counter
from math import ceil, sqrt, hypot, factorial, pi, sin, cos, radians
from itertools import permutations, combinations, product, accumulate
from operator import itemgetter, mul
from copy import deepcopy
from string import ascii_lowercase, ascii_uppercase, digits
from fractions import gcd

def input(): return sys.stdin.readline().strip()
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(): return list(map(int, input().split()))
sys.setrecursionlimit(10 ** 9)
INF = float('inf')
mod = 10 ** 9 + 7

K = INT()

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

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

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

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

    even = K // 2
    odd = K - even

    print(even * odd)

main()

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

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

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

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

Solution (Python):
import math
k= int(input())
i=k/2
print(math.floor(i*i))

Solution (Python):
import math

n = int(input())

print(math.floor(n/2)*math.ceil(n/2))

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

Solution (Python):
n = int(input())
g = []
k = []

for i in range(1,n+1):
    if i%2 == 0:
        g.append(i)
    else:
        k.append(i)

print(len(g)*len(k))

Solution (Python):
k=int(input())
ev=list(range(1,k+1))[1::2]
od=list(range(1,k+1))[0::2]
print(len(ev)*len(od))

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

Solution (Python):
def solve():
    n = int(input())
    e = [i for i in range(1, n + 1) if i % 2 == 0]
    o = [i for i in range(1, n + 1) if i % 2 == 1]
    return len(e) * len(o)


if __name__ == "__main__":
    print(solve())

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

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

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

Solution (Python):
k=int(input())
a=list(range(1,k+1))
a1=a[0::2]
a2=a[1::2]
print(len(a1)*len(a2))

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())

odd = K // 2
even = K // 2 + K % 2
print(odd*even)

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

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

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

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

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

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

print([(k//2)*(k//2),(k//2)*(k//2+1)][k%2==1])

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

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

Solution (Python):
def test():
    k = int(input())
    a = int(k/2)
    b = k - a
    print(a*b)


if __name__ == "__main__":
    test()

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

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

Solution (Python):
import math





inputa = input().split()





a = int(inputa[0])






odd =  int(math.floor((a+1) / 2))
even = int(math.floor(a / 2))

ans = odd * even
print(ans)

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(int((K**2)/4))
else:
  print(int(((K+1)/2)*((K-1)/2)))

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

Solution (Python):
import math
x = int(input())

if x%2 == 0:
  t = x/2
  print(math.ceil(t**2))
else:
  p = (x-1)/2
  q = (x+1)/2
  print(math.ceil(p*q))

Solution (Python):

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

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

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

num_even = K // 2
num_odds = K - K // 2

print(num_even * num_odds)

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

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

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

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

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

print(ans)

Solution (Python):
k=list(range(1,int(input())+1))
print(sum([len(k[i::2]) for i in k]))

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

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

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

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

print(e*o)

Solution (Python):
import scipy.misc as scm
N = int(input())

e = N //2
if N %2 == 0:
  print(scm.comb(e, 1, 1)*scm.comb(e, 1, 1))
else:
  print(scm.comb(e, 1, 1)*scm.comb(e+1, 1, 1))

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

Solution (Python):

K = int(input())
A = K // 2
K -= A
print(K * A)

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

Solution (Python):

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

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

Solution (Python):
a = int(input())
count_even = 0
count_odd = 0

for i in range(1, a + 1):
    if i % 2 == 0:
        count_even += 1
    else:
        count_odd += 1

print(count_even * count_odd)

Solution (Python):
n = int(input())
print(n // 2 * (n - n // 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())
if K%2==0:
	print(int((K/2)*(K/2)))
else:
	print(int(((K-1)/2)*((K+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):
import sys
input = sys.stdin.readline
from operator import itemgetter

def main():
	n = int(input().strip())
	print((n // 2) * ((n+1) // 2))

if __name__ == '__main__':
	main()

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

num = 0

for i in range(k, 0, -1):
  for j in range(i-1, 0, -2):
    num += 1
    
    
    
print(num)

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

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

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

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

Solution (Python):
from functools import reduce
import math

def main():
    
    
    
    

    
    
    
    
    
    

    
    

    
    
    
    
    
    
    
    
    
    INF = float("inf")

    
    MOD = 10**9+7
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    

    
    
    
    
    a = int(input())
    if a %2 ==1:        
        print((a//2) *(a//2 +1))
    else:
        print((a//2) * (a//2))
    
if __name__ == '__main__':
    main()

Solution (Python):
def main():
    N = int(input())
    half = int(N/2)

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


if __name__ == '__main__' :
    main()

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

Solution (Python):

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

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

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

Solution (Python):


K = int(input())

num = 0
for i in range(K):
    num += (K-i)//2
print(num)

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

if K%2==0:
    e = K//2
    o = K//2
else:
    e = K//2
    o = K//2 + 1

print(e*o)

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

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

Solution (Python):
import math
n = int(input())
if n % 2 == 1:
    print(round((n/2)**2))
else:
    print(round(n/2)**2)

Solution (Python):


def main():

    N = int(input())

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


        
    
if __name__== "__main__":
    main()

Solution (Python):
words = lambda t : list(map(t, input().split()))
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())
print((k//2)*(k-(k//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())
print(((k+1)//2)*(k//2))

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

Solution (Python):
K = int(input())
even_num = K // 2
odd_num = K - even_num

result = even_num * odd_num
print(result)

Solution (Python):

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

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

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

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

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

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

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

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

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

Solution (Python):

k=int(input())
a = k // 2
b = k - a
print(a*b)

Solution (Python):
n=int(input())
cnt=0
for i in range(1,n):
  for j in range(i+1,n+1):
    if i%2==0 and j%2==1:
      cnt+=1
    elif i%2==1 and j%2==0:
      cnt+=1
      
print(cnt)

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

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

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

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

Solution (Python):
k = int(input())
count1 = 0
count2 = 0
for i in range(k):
    if i % 2 == 0:
        count1 += 1
    else:
        count2 += 1
print(count1 * count2)

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

Solution (Python):
K = int(input())
answer = 0
for k in range(K):
  for l in range(k):
    if (k + l) % 2 == 1:
      answer += 1
print(answer)

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(int((K/2)**2))
else:
    print(int((K**2-1)/4))

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

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

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

even = K // 2

print(odd * even)

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

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

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

if K%2 == 0:
    print(K//2*K//2)
else:
    print(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):
K=int(input())
gu = K//2
ki = K -gu
print(gu*ki)

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

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

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

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

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

Solution (Python):
"""
1 以上 K 以下の偶数は K//2 個なので、K // 2 * (K - K // 2) が答えになる。
"""

K = int(input())
print(K // 2 * (K - K // 2))

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

Solution (Python):

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

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

Solution (Python):
import itertools

K = list(range(1,int(input())+1))
c = list(itertools.combinations(K, 2))
count = 0

for i in c:
  
  
  if i[0]%2==0 and i[1]%2==1 or i[0]%2==1 and i[1]%2==0:
    count+=1
    

print(count)

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

x=n//2
y=n-x

print(x*y)

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

print(-(-x//2) * (x//2))

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

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

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

if N % 2 == 0:
    print((N//2)**2)
else:
    print((N//2+1)*(N//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()
    a = n // 2
    b = n - a
    print(a*b)
    return


def B():
    x1, y1, x2, y2 = LI()
    a = x2 - x1
    b = y2 - y1
    print(x2 - b, y2 + a, x1 - b, y1 + a)
    return


def C():
    n, k = LI()
    if k % 2:
        print((n // k)** 3)
    else:
        print(int((n//k)**3 + ((n-k/2)//k+1)**3))
        
    return


def D():
    return


def E():
    return


def F():
    return


def G():
    return


def H():
    return


if __name__ == '__main__':
    A()

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

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

odd = (n + 1) // 2
even = n // 2
print(odd * even)

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

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)
B=int(K-A)

print(A*B)

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

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

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

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

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

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

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

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

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())
print((k//2)*(-(-k//2)))

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

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

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

Solution (Python):


n = int(input())


odd = (n+1)//2
even = n//2
print(odd*even)

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

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

resolve()

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

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

even = K//2
odd = K-even

print(even*odd)

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

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

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

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

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

if a%2==0:
  print(int((0.5*a)**2))
else:
  print(int(0.5*(a-1)*0.5*(a+1)))

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

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

Solution (Python):



K = int(input())


even = 0
odd = 0

for i in range(K):
    if i % 2 == 0:
        even += 1
    else:
        odd += 1


print(even * odd)

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

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

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

Solution (Python):



K = int(input())
counter = 0

for i in range(K):
    for j in range(i, K):
        if (i % 2 == 0 and j % 2 != 0) or (i % 2 != 0 and j % 2 == 0):
            counter += 1

print (counter)

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

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

Solution (Python):
K = int(input())
odds = []
evens = []
for x in range(K):
  x+=1
  if x%2 == 0:
    evens.append(x)
  else:
    odds.append(x)
print(len(evens)*len(odds))

Solution (Python):
nl = lambda: list(map(int, input().split()))
sl = lambda: input().split()
n = lambda: int(input())
s = lambda: input()

K = n()
k = K // 2

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

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

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//2+n%2))

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

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

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

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

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

even = K // 2
odd = K // 2
if K % 2:
    odd = K // 2 + 1

print(even * odd)

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

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

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

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

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

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

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

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

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

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

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

Solution (Python):

k = int(input())


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


print(int(answer))

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

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

import sys


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



def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    K = int(next(tokens))  
    solve(K)

if __name__ == '__main__':
    main()

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

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

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

even = K // 2
odd = K - even
print(even * odd)

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

Solution (Python):

k = int(input())

ans = (k //2 + k%2)*( k//2)
print(ans)

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


abc()

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

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

a = n // 2
b = (n+1) // 2
print(a*b)

Solution (Python):
k = int(input())
from math import floor
print(floor(k/2)*(k - floor(k/2)))

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

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

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

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

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

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

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

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

def guuki(num):
    if num%2 == 0:
        return 0
    else:
        return 1

if k == 1:
    print(1)
elif guuki(k) == 0:
    print(math.ceil(k/2 * k/2))
else:
    print(math.ceil((k+1)/2 * (k-1)/2))

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//2+n%2))

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

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

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

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

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

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

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

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

from itertools import combinations

ls = [int(x) for x in range(1,k+1)]

com = combinations(ls,2)

flg = 0
for i in com:
    if sum(i)%2 == 1:
        flg += 1

print(flg)

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

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

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

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

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

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

Solution (Python):


k = int(input())

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

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

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

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

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

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

oddl = []
evenl = []

for i in range(a):
    if i%2 == 1:
        oddl.append(i)
    else:
        evenl.append(i)

odd = len(oddl)
even = len(evenl)

print(odd*even)

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

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

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

Solution (Python):
import itertools
import math

K = int(input())


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

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

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

print(int(ans))

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

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

ans = int(k/2) * int((k+1)/2)

print(ans)

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

even = N // 2
odd = N - even
print(even * odd)

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

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

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

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

e = k // 2
o = (k+1) // 2

print(e*o)

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

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

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

Solution (Python):
import itertools
n = int(input())
l = []
for i in range(1,n+1):
  l.append(i)
com = list(itertools.combinations(l,2))
cnt = 0
for i in range(len(com)):
  if com[i][0] % 2 == 0 and com[i][1] % 2 == 1 or com[i][0] % 2 == 1 and com[i][1] % 2 == 0:
    cnt += 1
print(cnt)

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

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())
print((k//2)*(k-k//2))

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

Solution (Python):
import sys, os

f = lambda:list(map(int,input().split()))
if 'local' in os.environ :
    sys.stdin = open('./input.txt', 'r')

def solve():
    k = f()[0]
    even = k//2
    odd = k - even
    print(even*odd)

solve()

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

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

e = int(K/2)
o = K - e

print(e * o)

Solution (Python):
import sys
import bisect
input = sys.stdin.readline

K = int(input())

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

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

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

if not K % 2:
    print((K // 2) ** 2)
else:
    print((K // 2 + 1) * (K // 2))

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

Solution (Python):
k = int(input())
half = k // 2
two = half
one = half
if k % 2 != 0:
    one = half + 1
print(one * two)

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

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

e = K // 2
if K % 2 == 1:
    o = K // 2 + 1
else:
    o = K // 2

print(e * o)

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

Solution (Python):
k=int(input())
if k%2==0:
  print(int(k*k/4))
else:
  a=k/2+0.5
  b=k//2
  print(int(a*b))

Solution (Python):

import sys


def solve(K: int):
    ne = K // 2
    no = ne + K % 2

    print(int(ne*no))
    return



def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    K = int(next(tokens))  
    solve(K)

if __name__ == '__main__':
    main()

Solution (Python):
from sys import stdin

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

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

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

print(int((a/2)*(a/2)))

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

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

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

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