Buggy python submission (verdict: Runtime Error):
import sys, re
from collections import deque, defaultdict, Counter
from math import ceil, sqrt, hypot, factorial, pi, sin, cos, tan, asin, acos, atan, radians, degrees#, log2
from itertools import accumulate, permutations, combinations, combinations_with_replacement, product, groupby
from operator import itemgetter, mul
from copy import deepcopy
from string import ascii_lowercase, ascii_uppercase, digits
from bisect import bisect, bisect_left
from fractions import gcd
from heapq import heappush, heappop
from functools import reduce
def input(): return sys.stdin.readline().strip()
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(): return list(map(int, input().split()))
def ZIP(n): return zip(*(MAP() for _ in range(n)))
sys.setrecursionlimit(10 ** 9)
INF = float('inf')
mod = 10 ** 9 + 7

N = INT()
A = [INT() for _ in range(N)]	

#dic = defaultdict(int)

for a in A:
	print(dic[a])
	dic[a] ^= 1

print(dic)
ans = 0
for x in dic:
	ans += dic[x]
print(ans)
	


Fixed submission:
import sys, re
from collections import deque, defaultdict, Counter
from math import ceil, sqrt, hypot, factorial, pi, sin, cos, tan, asin, acos, atan, radians, degrees#, log2
from itertools import accumulate, permutations, combinations, combinations_with_replacement, product, groupby
from operator import itemgetter, mul
from copy import deepcopy
from string import ascii_lowercase, ascii_uppercase, digits
from bisect import bisect, bisect_left
from fractions import gcd
from heapq import heappush, heappop
from functools import reduce
def input(): return sys.stdin.readline().strip()
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(): return list(map(int, input().split()))
def ZIP(n): return zip(*(MAP() for _ in range(n)))
sys.setrecursionlimit(10 ** 9)
INF = float('inf')
mod = 10 ** 9 + 7

N = INT()

num = defaultdict(int)

for _ in range(N):
	A = INT()
	num[A-1] ^= 1

ans = 0
for x in num:
	ans += num[x]

print(ans)

Buggy python submission (verdict: Runtime Error):
import sys, re
from math import ceil, sqrt, hypot, factorial, pi, sin, cos, tan, asin, acos, atan, radians, degrees#, log2
from collections import deque, defaultdict, Counter
from itertools import accumulate, permutations, combinations, combinations_with_replacement, product, groupby
from operator import itemgetter, mul
from copy import deepcopy
from string import ascii_lowercase, ascii_uppercase, digits
from bisect import bisect, bisect_left
from fractions import gcd
from heapq import heappush, heappop, heapify
from functools import reduce
def input(): return sys.stdin.readline().strip()
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(): return list(map(int, input().split()))
def ZIP(n): return zip(*(MAP() for _ in range(n)))
sys.setrecursionlimit(10 ** 9)
INF = float('inf')
mod = 10 ** 9 + 7

N, M, R = MAP()
r = LIST()
dist_matrix = [[INF]*N for _ in range(N)]

for _ in range(M):
	A, B, C = MAP()
	dist_matrix[A-1][B-1] = C
	dist_matrix[B-1][A-1] = C

for i in range(N):
	dist_matrix[i][i] = 0

#for i in range(N):
#	print(dist_matrix[i])
#print()

def Warshall_Floyd(dist, N):
	for k in range(N):
		for i in range(N):
			for j in range(N):
				dist[i][j] = min(dist[i][j], dist[i][k] + dist[k][j])

Warshall_Floyd(dist_matrix, N)

#for i in range(N):
#	print(dist_matrix[i])


ans = INF
for x in permutations(r):
	tmp = x[0]
	dis = 0
	for i in range(1, R):
		dis += dist_matrix[tmp-1][x[i]-1]
		tmp = x[i]
	ans = min(ans, dis)
	
print(int(ans))





Fixed submission:
import sys, re
from collections import deque, defaultdict, Counter
from math import ceil, sqrt, hypot, factorial, pi, sin, cos, tan, asin, acos, atan, radians, degrees#, log2
from itertools import accumulate, permutations, combinations, combinations_with_replacement, product, groupby
from operator import itemgetter, mul
from copy import deepcopy
from string import ascii_lowercase, ascii_uppercase, digits
from bisect import bisect, bisect_left
from fractions import gcd
from heapq import heappush, heappop
from functools import reduce
def input(): return sys.stdin.readline().strip()
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(): return list(map(int, input().split()))
def ZIP(n): return zip(*(MAP() for _ in range(n)))
sys.setrecursionlimit(10 ** 9)
INF = float('inf')
mod = 10 ** 9 + 7

N = INT()

num = defaultdict(int)

for _ in range(N):
	A = INT()
	num[A-1] ^= 1

ans = 0
for x in num:
	ans += num[x]

print(ans)