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

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

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

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

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

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

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

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

a = x // 2
b = x - a

print(a*b)

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

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

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

Solution (Python):
import math

k= int(input())

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

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

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

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

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

Solution (Python):
n=int(input())
n in range(2,101)
if n%2==0:
    even=odd=n//2
    print(even*odd)
else:
    even=n//2
    odd=even+1
    print(even*odd)

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

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

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

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

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  = list(range(1,K+1,2))

even = list(range(2,K+1,2))
print(len(odd)*len(even))

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

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

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

Solution (Python):


N = int(input().split()[0])

odd_n = (N + 1) // 2
even_n = N // 2

ans = odd_n * even_n
print(ans)

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

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

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

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

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

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

Solution (Python):
k = int(input())
n = k//2

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

Solution (Python):
if __name__ == '__main__':
    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())
if k%2==0:
  print((k//2)**2)
else:
  a = (k-1)//2
  print(a*(k-a))

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

Solution (Python):
import math

k = int(input())
a = math.ceil(k / 2)
b = math.floor(k / 2)
print(a * b)

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

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

Solution (Python):
k = int(input())
 
even_list = []
odd_list = []
 
is_odd = True
for j in range(1, k + 1):
    if is_odd:
        odd_list.append(j)
    else:
        even_list.append(j)
    is_odd = not is_odd
 
print(int(len(even_list) * len(odd_list)))

Solution (Python):
k = int(input())
 
even_list = []
odd_list = []
 
is_odd = True
for i in range(1, k + 1):
    if is_odd:
        odd_list.append(i)
    else:
        even_list.append(i)
    is_odd = not is_odd
 
print(int(len(even_list) * len(odd_list)))

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

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

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

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

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

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

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

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

output = [[a, b] for a in even
              for b in odd]
print(len(output))

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

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

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

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

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


pair()

Solution (Python):
k=int(input())
if (k<2):
      pass
else:
      n= k//2
      print(n*(k-n))

Solution (Python):
N =int(input())
if N%2==1:
    even =N//2
    odd = N-even

else:
    even = N/2
    odd = N/2
print(int(even*odd))

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

a = K//2

if K % 2 == 0:
  print(a ** 2)
  
else:
  print(a * (K-a))

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

Solution (Python):
import math

k= int(input())

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

Solution (Python):
k=input()
k=int(k)
if k%2==0:
    even = k/2
    odd = k/2
else:
    even = k//2
    odd = k - even

print(int(even*odd))

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

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

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

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

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

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+1)//2))

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

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())
even, odd = 0,0


if K % 2 == 0:
  even = K // 2
  odd = K // 2 
  
elif K % 2 == 1:
  even = K // 2
  odd = K // 2 + 1
  
print( even * odd)

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

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

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

even=K//2
odd=K//2+K%2

print(even*odd)

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

evens = [i for i in range(k) if i % 2 == 0]
odds = [j for j in range(k) if j % 2 != 0]

print(len(evens) * len(odds))

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

Solution (Python):
'''A - Pair
https://atcoder.jp/contests/abc108/tasks/abc108_a

>>> main(3)
2
>>> main(6)
9
>>> main(11)
30
>>> main(50)
625'''

from itertools import permutations


def main(k):
    count = 0

    for p in permutations(range(1, k + 1), 2):
        if p[0] % 2 == 0 and p[1] % 2 != 0:
            count += 1

    print(count)


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

Solution (Python):

K = int(open(0).read())
print((K//2)**2 if K%2==0 else (K//2)*(-(-K//2)))

Solution (Python):
n = int(input())
cnt = []
for i in range(1, n + 1):
    if i % 2 == 0:
        for j in range(1, n + 1):
            if j % 2 != 0:
                cnt.append([i,j])
print(len(cnt))

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

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

Solution (Python):
n = int(input().split()[0])

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

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

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

Solution (Python):
K = int(input())
nums = [i for i in range(1, K+1)]
evens = nums[1::2]
odds = nums[0::2]

s = set()
for e in evens:
    for o in odds:
        s.add((e, o))
print(len(s))

Solution (Python):
K = int(input())
def f(N):
    if N == 2:
        return 1
    if N % 2 == 0:
        return f(N-1)+(N//2)
    else:
        return f(N-1)+((N-1)//2)
print(f(K))

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

even_num = int(K / 2)

print(int((K - even_num) * even_num))

Solution (Python):
K = int(input())
guu = 0
ki = 0
for i in range(1, K+1):
  if i % 2 == 0:
    guu += 1
  else:
    ki += 1
print(guu*ki)

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

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

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

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

print(math.ceil(a/2) * (a//2))

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

Solution (Python):
import sys

input = sys.stdin.readline


def main():
    k = int(input())
    print(k // 2 * (k - (k // 2)))


if __name__ == "__main__":
    main()

Solution (Python):
K=int(input())
if K%2==0:
  print(K*K//4)
else:
  print(((K+1)//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):
def slove():
    import sys
    input = sys.stdin.readline
    n = int(input().rstrip('\n'))
    o = n - n // 2
    e = n // 2
    print(o * e)


if __name__ == '__main__':
    slove()

Solution (Python):
from math import floor,ceil

k = int(input())
print(ceil(k/2) * floor(k/2))

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

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

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

Solution (Python):
ni = lambda: int(input())
nm = lambda: map(int, input().split())
nl = lambda: list(map(int, input().split()))

k = ni()

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

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

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

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())

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

print(even * odd)

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

if k%2 ==0 :
  s = k*k
  s1 = s//4
  print(s1)
else:
  s = k//2
  s1 = s*(s+1)
  print(s1)

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

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

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

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

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

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

print(count)

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

e = 0
o = 0

for i in range(1,K+1):
  if i % 2 == 0:
    e += 1
  if i % 2 == 1:
    o += 1
    
print(e*o)

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

odd_cnt = 0
even_cnt = 0
for i in range(1, K+1):
    if i % 2 == 0:
        even_cnt += 1
    else:
        odd_cnt += 1

print(even_cnt * odd_cnt)

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

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

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

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

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

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

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

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

o = (n//2)*(n//2 + n%2)
print(o)

Solution (Python):
t = int(input())
print((t // 2) * (t // 2 + t % 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):
import os, sys, re, math

def doit(n):
    if n % 2 == 1:
        return ((n // 2) + 1) * (n // 2)
    else:
        return (n // 2) ** 2

K = int(input())
print(doit(K))

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

print(a*b)

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

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

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

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

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

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

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

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

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

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

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

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

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

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

e = n//2
o = n-e

print(e*o)

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

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

Solution (Python):


def main():
    K  = int(input())
    if K % 2 == 0:
        print((K//2)**2)
    else:
        print((K//2)*(K//2+1))
        
if __name__ == '__main__':
    main()

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

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

Solution (Python):
import sys

if sys.platform =='ios':
    sys.stdin=open('input_file.txt')
    
n=int(input())

print((n//2)*(n-(n//2)))

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

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())

even = 0
odd = 0

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

print(even * odd)

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

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

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

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

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

if K % 2 == 0:
    S = round((K / 2))
else:
    S = round((K - 1) / 2)

X = S * (K - S)

print(X)

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

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

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

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

even_num = K // 2
odd_num = K - even_num
print(even_num * odd_num)

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

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

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

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

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

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

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())
count = 0
for i in range(1,k+1):
  if i % 2 == 0:
    count += 1
print(count * (k - count))

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

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

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

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

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

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

Solution (Python):

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

Solution (Python):
x,y = divmod(int(input()),2)
print(x*(x+y))

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

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

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

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

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

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

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

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

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

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

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

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

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

Solution (Python):
n = int(input())
cand = []
output = []
for i in range(1, n + 1):
    cand.append(i)
for i in range(len(cand)):
    for j in range(len(cand)):
        if cand[i] % 2 == 0 and cand[j] % 2 == 1:
            output.append((cand[i], cand[j]))
        elif cand[i] % 2 == 1 and cand[j] % 2 == 0:
            output.append((cand[i], cand[j]))
print(int(len(output) / 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 main():
    K = int(input())
    even = K//2
    odd = K - even
    
    print(even*odd)

if __name__ == "__main__":
    main()

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

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

Solution (Python):
import sys

stdin = sys.stdin

ni = lambda: int(ns())
na = lambda: list(map(int, stdin.readline().split()))
ns = lambda: stdin.readline().rstrip()  

k = ni()
a = k // 2
b = k - a
print(a * b)

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

Solution (Python):
max_num = int(input())
ls_all = [x for x in range(1, max_num + 1)]
ls_even = ls_all[::2]
ls_odd = ls_all[1::2]
answer = len(ls_even) * len(ls_odd)
print(int(answer))

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

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

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

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

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

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

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

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

if n % 2 == 0:
  print(n**2 // 4)
else:
  print((n**2 - 1)//4)

Solution (Python):

k = int(input())

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

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

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

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

even = k // 2
odd = even if k % 2 == 0 else even + 1

print(odd * even)

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

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

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

Solution (Python):
k = int(input())
pair = []
if 2 <= k <= 100:
    for i in range(1, k + 1):
        if 0 == i % 2:
            for j in range(1, k + 1):
                if 1 == j % 2:
                    pair.append((i, j))
                else:
                    continue
        else:
            continue
    
    print(len(pair))
else:
    print('hoge!')

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

Solution (Python):
n=int(input())
even=[i for i in range(n) if i%2==1]
odd=[i for i in range(n) if i%2==0]

print(len(even)*len(odd))

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())

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

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

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

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

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

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

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

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

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

Solution (Python):


K = int(input())

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

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

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

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

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

Solution (Python):
def main():
    K = int(input())
    even = K // 2
    odd = K - even
    return even * odd
    
if __name__ == '__main__':
    print(main())

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

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

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

Solution (Python):
import math
a=int(input())
if a%2==0:
  print(int(a*a/4))
else:
  print(math.ceil(a/2)*math.floor(a/2))

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

X=K//2
Y=K%2
print(X**2 if Y==0 else X**2+X)

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

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

even_list = []
odd_list = []

is_odd = True
for i in range(1, k + 1):
    if is_odd:
        odd_list.append(i)
    else:
        even_list.append(i)
    is_odd = not is_odd

print(int(len(even_list) * len(odd_list)))

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

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

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

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

Solution (Python):
import math
import sys
import queue
from collections import Counter
from itertools import accumulate
from fractions import gcd
from functools import reduce


def lcm(a, b):
    return a * b // gcd(a, b)

def combination_count(n, r):
    return math.factorial(n) // (math.factorial(n - r) * math.factorial(r))

def permutations_count(n, r):
    return math.factorial(n) // math.factorial(n - r)

sys.setrecursionlimit(10000)

mod = 1000000007

"""

a = 100
b = 0.987654321
print("{0:06d}-{1:6f}".format(a,b))
000100-0.987654


char_list = list("abcd") 



    = sys.stdin.readline().rstrip()
    = list(sys.stdin.readline().rstrip())


    = int(sys.stdin.readline())
    = map(int, sys.stdin.readline().split())
    = list(map(int, sys.stdin.readline().split()))
    = [list(map(int,list(sys.stdin.readline().split()))) for i in range(N)]
"""

if __name__ == "__main__":
    K = int(sys.stdin.readline())
    o = K // 2
    e = K - o
    print(o * e)

Solution (Python):
import math
import sys
import queue
from collections import Counter
from itertools import accumulate
from fractions import gcd
from functools import reduce


def lcm(a, b):
    return a * b // gcd(a, b)

def combination_count(n, r):
    return math.factorial(n) // (math.factorial(n - r) * math.factorial(r))

def permutations_count(n, r):
    return math.factorial(n) // math.factorial(n - r)

sys.setrecursionlimit(10000)

mod = 1000000007

"""

a = 100
b = 0.987654321
print("{0:06d}-{1:6f}".format(a,b))
000100-0.987654


char_list = list("abcd") 



    = sys.stdin.readline().rstrip()
    = list(sys.stdin.readline().rstrip())


    = int(sys.stdin.readline())
    = map(int, sys.stdin.readline().split())
    = list(map(int, sys.stdin.readline().split()))
    = [list(map(int,list(sys.stdin.readline().split()))) for i in range(N)]
"""

if __name__ == "__main__":
    K = int(sys.stdin.readline())
    ans = 0
    for i in range(1, K + 1):
        for j in range(i + 1, K + 1):
            if i % 2 == 0:
                if j % 2 != 0:
                    ans += 1
            else:
                if j % 2 == 0:
                    ans += 1
    print(ans)

Solution (Python):
k = int(input())
cnt_odd = 0
cnt_even = 0
if k&1:
    while k >= 1:
        cnt_odd += 1
        k -= 2
    cnt_even = cnt_odd - 1
else:
    while k > 0:
        cnt_even += 1
        k -= 2
    cnt_odd = cnt_even

print(cnt_even * cnt_odd)

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

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


K_1 = K//2
K_2 = K-K_1

print(K_1*K_2)