#!/usr/bin/python
func = lambda a, b, c, d, r: [map(int, (a, b, c, d))] + [r=='YES']

N = int(raw_input())
al = range(10)
ok = set(al)
ng = set()
for _ in xrange(N):
    nums, yes = func(*raw_input().split())
    if yes:
        ok &= set(nums)
    else:
        ng |= set(nums)
ok &= set(al) - ng
print list(ok)[0]