n=int(input())
c={}
c[0]=1
for i in range(n):
    nc={}
    for j in c:
        if j>=0:
            if j+1 in nc:
                nc[j+1]+=c[j]
            else:
                nc[j+1]=c[j]
            if j-1 in nc:
                nc[j-1]+=c[j]
            else:
                nc[j-1]=c[j]
    c=nc
print(c[0])