I know ordered dictionaries are the norm in modern versions of py3, but added the import just for the spirit of things.

from collections import OrderedDict as od

if __name__ == '__main__':
    n = int(input())
    dic = od()
    for i in range(n):
        product, price = input().rsplit(' ', 1)
        dic[product] = int(price) + dic.get(product, 0)
    print(*(f"{k} {v}" for k, v in dic.items()), sep='\n')

from collections import OrderedDict

n = int(input()) items = OrderedDict()

for i in range(n): item, price = input().rsplit(' ', 1) net_price = int(price) if item in items: items[item] += net_price else: items[item] = net_price

for item, net_price in items.items(): print(item, net_price)

from collections import OrderedDict
d=OrderedDict()
n=int(input())
for i in range(0,n):
    l=input().rsplit(' ',1)
    d[l[0]]= int(l[1])+int(d.get(l[0],0))
    #print(l,d)
for k,v in d.items():
    print(k, v)

As i was not sure whats special about orderd dict i searched a bit in stackoverflow and found this gold .Hope this helps you as well

difference-between-dictionary-and-ordereddict

As of Python 3.7, a new improvement to the dict built-in is:

the insertion-order preservation nature of dict objects has been declared to be an official part of the Python language spec.

This means there is no real need for OrderedDict anymore 🎉. They are almost the same.

Some minor details to consider... Here are some comparisons between Python 3.7+ dict and OrderedDict:

from collections import OrderedDict

d = {'b': 1, 'a': 2} od = OrderedDict([('b', 1), ('a', 2)])

they are equal with content and order

assert d == od assert list(d.items()) == list(od.items()) assert repr(dict(od)) == repr(d) Obviously, there is a difference between the string representation of the two object, with the dict object in more natural and compact form.

str(d) # {'b': 1, 'a': 2} str(od) # OrderedDict([('b', 1), ('a', 2)]) As for different methods between the two, this question can be answered with set theory:

d_set = set(dir(d)) od_set = set(dir(od)) od_set.difference(d_set)

{'dict', 'reversed', 'move_to_end'} for Python 3.7

{'dict', 'move_to_end'} for Python 3.8+

This means OrderedDict has at most two features that dict does not have built-in, but work-arounds are shown here:

Workaround for reversed / reversed() No workaround is really needed for Python 3.8+, which fixed this issue. OrderedDict can be "reversed", which simply reverses the keys (not the whole dictionary):

reversed(od) # list(reversed(od)) # ['a', 'b']

with Python 3.7:

reversed(d) # TypeError: 'dict' object is not reversible list(reversed(list(d.keys()))) # ['a', 'b']

with Python 3.8+:

reversed(d) # list(reversed(d)) # ['a', 'b'] To properly reverse a whole dictionary using Python 3.7+:

dict(reversed(list(d.items()))) # {'a': 2, 'b': 1} Workaround for move_to_end OrderedDict has a move_to_end method, which is simple to implement:

od.move_to_end('b') # now it is: OrderedDict([('a', 2), ('b', 1)])

d['b'] = d.pop('b') # now it is: {'a': 2, 'b': 1}