def my_func(data): res = dict() pairs = data[1:] for i in pairs: ind, ind_value = i.split(" ") if ind not in res: res[ind] = ind_value else: res[ind] = str(int(res[ind]) + int(ind_value)) temp = sorted(res.items(), key=lambda x :int(x[0]), reverse=False) for key, value in temp: print(f"{key} {value}") data = [] while True: try: data.append(input()) except (EOFError, KeyboardInterrupt): break my_func(data)