# coding: utf-8
# Here your code !

N = int(input())

ans_opption = [0,1,2,3,4,5,6,7,8,9]

for i in range(N):
    num = input().split()
    #print(num) 
    
    if num[4] == "YES":
            
        for i in range(len(ans_opption)):
            if str(i) not in num:
                ans_opption[i] = "x"
                #print(ans_opption)                                              #デバック行
                
                    
    elif num[4] == "NO":

        for i in range(len(ans_opption)):
            if str(i) in num:
                ans_opption[i] = "x"
                    
            else:
                pass
                
for i in range(len(ans_opption)):
    if "x" in ans_opption:
        ans_opption.remove("x")  
    else:
        pass    
    
print(ans_opption[0])