#!/usr/local/bin/python3

sta = 'yamada'
b = [('suzuki', 'satou'), ('yamada', 'tanaka'), ('tanaka', 'satou'), ('watanabe', 'suzuki')]

nodes = {}
runners = set()
for x, y in b:
    nodes.setdefault(x, []).append(y)
    nodes.setdefault(y, []).append(x)
    runners.add(x)
    runners.add(y)

baton_holder = sta
ans = [baton_holder]

for _ in range(len(runners)-1):
    runners.remove(baton_holder)
    candidates = nodes[baton_holder]
    for baton_holder in candidates:
        if baton_holder in runners:
            break
    ans.append(baton_holder)

print(ans)