in_file=open("DATA4.txt","r")
out_file=open("OUT4.txt","w")
done = 0

for i in range (1,6):
    done = 0
    words=in_file.readline()
    length = len(words)-1
    lst = list(words)
    
    
    letters = ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P' , 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z']
    lettercounter = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

    for i2 in range (int(length)):
        for i3 in range (26):
            if lst[int(i2)] == letters[int(i3)]:
                lettercounter[i3] = lettercounter[i3] + 1

    for i4 in range (int(length)):
        for i5 in range(26):
                if (lst[i4] == letters[i5]) and (lettercounter[i5] == 1) and (done == 0):
                    textout=out_file.write(str(lst[i4])+"\n")
                    done = 1
                    
                    
            


in_file.close()
out_file.close()