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])