import sys map = {} for line in sys.stdin: a = line.split() if len(a)== 1 : continue k,v=int(a[0]),int(a[1]) if k in map.keys(): map[k] = int(map[k]) + int(v) else: map[k] = v // 用dict存键值对,方便排序和索引 list = sorted(map.keys()) for i in list: print(str(i)+" "+str(map[i]))