find_unique_items.py

//Previous code
a = list(map(int, raw_input().split()))
for i in a:
    if a.count(i) == 1:
        print i
        break


// Current code
from collections import Counter
a = list(map(int, raw_input().split()))
b = Counter(a)
onlies = [k for k,v in b if v == 1]
print onlies


# one way using sets
present = set()
morelies = set()

for i in a:
    if i in present:
        morelies.add(i)
    else:
        present.add(i)

onlies = present - morelies
print(onlies)


# another way using sets
onlies = set()
morelies = set()

for i in a:
    if i in morelies:
        pass
    elif i in onlies:
        morelies.add(i)
        onlies.remove(i)
    else:
        onlies.add(i)

print(onlies)