import sys if __name__=="__main__": inputSlice=list(sys.stdin) count_=int(inputSlice[0]) map={} for i in range(count_): thisItemSlice=inputSlice[i+1].split(" ") key=thisItemSlice[0] map[key]=map.get(key,0)+int(thisItemSlice[1]) items=sorted([item for item in map.items()],key=lambda item:int(item[0])) for item in items: print(item[0],item[1])