n=int(input())
data=[input().split() for i in range(n)]
d=[int(s) for s in list("0123456789")]
d_2=[]
for i in range(n):
    if data[i][4]=="NO":
        for j in range(4):
            d[int(data[i][j])]=-1
    else:
        for j in range(4):
            d_2.append(int(data[i][j]))
d_3=[]
for i in range(10):
    if d[i]>=0:
        d_3.append(d[i])
if len(d_3)==1:
    print(d_3[0])
else:
    for i in range(len(d_3)):
        if d_3[i] in d_2:
            print(d_3[i])
            break