info = open("DATA4.txt", "r")
put = open("OUT4.txt", "w")

c = info.readline()

while c!="":
    word = c.strip("/n")
    c = info.readline()
    asd = len(word)

    count = 0
    done = 0
    
    while asd != 0:
        if word.count(str(word[int(count)])) == 1:
            pure = word[count]
            put.write(str(pure)+"\n")
            
            break
        else:
            count = count + 1
            asd = asd-1
put.close()