b=[]
c=[]
a=list(map(int, input().split()))
for i in range(len(a)):
        if i.index%2 == 0:
                b.append(a[i])
                i+=1
        elif i.index%2 != 0:
                c.append(a[i+1])
                i+=1
else:
        print(' '.join(map(str,b+c)))