s = ["kk is iu ", "kk isgdf ", "kk isiurgdf", "kk is gsdfgdfg"] res = "" temp = s[0] for i in range(1,len(s)): for j in range(len(s[i])): try: if(s[i][j] == temp[j]): print(s[i][j]) res += s[i][j] print(res ) else: temp = res break except IndexError: continue # print(s[i][j],temp[j]) print(temp)