import sys
sys.setrecursionlimit(10 ** 8)
N = int(input())
vu = []
res = 0


def dfs(h, w):
    global res
    if h < 0 or w < 0 or w >= N:
        return
    if (h,w) in vu:
        return

    vu.append((h,w))
    res += 1
    for j in [1,-1]:
        dfs(h-2, w+j)

dfs(N-1, (N-1)//2)
#print(vu)
print(res)