题解 | #统计运动会项目报名人数#

import sys

import pandas as pd 
items = pd.read_csv('items.csv')
signup = pd.read_csv('signup.csv')
df = items.merge(signup, how = 'left', on = 'item_id')
print(df.groupby('item_name')['name'].count())

for line in sys.stdin:
    a = line.split()
    print(int(a[0]) + int(a[1]))