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