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