Whats wrong with my python program? CHFPLN july cookoff

from collections import Counter
test=int(input())

for _ in range(test):
n=int(input())
list=map(int,input().split())

frequency=Counter(list)
key=frequency.keys()
count=0
for i in key:
    no_of_sets=i//2
    
    if no_of_sets >= frequency[i]:
        count+=frequency[i]
    else:
        count+=no_of_sets
    
print(count)

Try replacing this with

no_of_sets = i - 1