# coding:utf-8

import collections

n = int(input())

yes_num = []
no_num = []
taro_list = []
for i in range(n):
    taro_list.append(input().split())

for j in range(n):
    for k in range(4):
        if taro_list[j][4] == 'NO':
            no_num.append(taro_list[j][k])
        else:
            yes_num.append(taro_list[j][k])

for l in yes_num:
    if l in no_num:
        yes_num.remove(l)
    else:
        continue

ans = collections.Counter(yes_num)
print(ans.most_common()[0][0])