Buggy python submission (verdict: Runtime Error):
# ABC073C - Write and Erase
def main():
    N, *A = map(int, open(0).read().split())
    store = set()
    for a in range(n):
        if a in store:
            store.remove(a)
        else:
            store.add(a)
    ans = len(store)
    print(ans)


if __name__ == "__main__":
    main()

Fixed submission:
# ABC073C - Write and Erase
import sys
input = sys.stdin.readline

n = int(input())
arr = set()
for _ in range(n):
    m = int(input())
    if m in arr:
        arr.remove(m)
    else:
        arr.add(m)
print(len(arr))

Buggy python submission (verdict: Time Limit Exceeded):
# ABC073C - Write and Erase
import sys
input = sys.stdin.readline

n = int(input())
arr = list(map(int, [input().rstrip() for _ in range(n)]))
st = set(arr)
cnt = 0
for i in st:
    if arr.count(i) % 2 == 1:
        cnt += 1
print(cnt)

Fixed submission:
# ABC073C - Write and Erase
import sys
input = sys.stdin.readline

n = int(input())
arr = set()
for _ in range(n):
    m = int(input())
    if m in arr:
        arr.remove(m)
    else:
        arr.add(m)
print(len(arr))

Buggy python submission (verdict: Time Limit Exceeded):
# ABC073C - Write and Erase
import sys
input = sys.stdin.readline

n = int(input())
arr = list(map(int, [input().rstrip() for _ in range(n)]))
st = set(arr)
cnt = 0
for i in st:
    if arr.count(i) % 2 == 1:
        cnt += 1
print(cnt)

Fixed submission:
# ABC073C - Write and Erase
import sys
input = sys.stdin.readline

n = int(input())
arr = set()
for _ in range(n):
    m = int(input())
    if m in arr:
        arr.remove(m)
    else:
        arr.add(m)
print(len(arr))

Buggy python submission (verdict: Time Limit Exceeded):
# ABC073C - Write and Erase
import sys
input = sys.stdin.readline

n = int(input())
arr = []
for _ in range(n):
    m = int(input())
    if m in arr:
        arr.remove(m)
    else:
        arr += [m]
print(len(arr))

Fixed submission:
# ABC073C - Write and Erase
import sys
input = sys.stdin.readline

n = int(input())
arr = set()
for _ in range(n):
    m = int(input())
    if m in arr:
        arr.remove(m)
    else:
        arr.add(m)
print(len(arr))

Buggy python submission (verdict: Time Limit Exceeded):
# ABC073C - Write and Erase
import sys
input = sys.stdin.readline

n = int(input())
arr = []
for _ in range(n):
    m = int(input())
    if m in arr:
        arr.pop(arr.index(m))
    else:
        arr += [m]
print(len(arr))

Fixed submission:
# ABC073C - Write and Erase
import sys
input = sys.stdin.readline

n = int(input())
arr = set()
for _ in range(n):
    m = int(input())
    if m in arr:
        arr.remove(m)
    else:
        arr.add(m)
print(len(arr))

Buggy python submission (verdict: Time Limit Exceeded):
# ABC073C - Write and Erase
n = int(input())
arr = []
for _ in range(n):
    m = int(input())
    if m in arr:
        arr.pop(arr.index(m))
    else:
        arr += [m]
print(len(arr))

Fixed submission:
# ABC073C - Write and Erase
import sys
input = sys.stdin.readline

n = int(input())
arr = set()
for _ in range(n):
    m = int(input())
    if m in arr:
        arr.remove(m)
    else:
        arr.add(m)
print(len(arr))

Buggy python submission (verdict: Runtime Error):
# ABC073C - Write and Erase
import sys
input = sys.stdin.readline

n = int(input())
arr = [0] * (10 ** 9 + 1)
cnt = 0
for _ in range(n):
    m = int(input())
    if arr[m] == 0:
        arr[m] = m
    else:
        arr[m] = 0
for i in arr:
    if i != 0:
        cnt += 1
print(cnt)

Fixed submission:
# ABC073C - Write and Erase
import sys
input = sys.stdin.readline

n = int(input())
arr = set()
for _ in range(n):
    m = int(input())
    if m in arr:
        arr.remove(m)
    else:
        arr.add(m)
print(len(arr))

Buggy python submission (verdict: Time Limit Exceeded):
# ABC073C - Write and Erase
import sys
input = sys.stdin.readline

n = int(input())
arr = []
for _ in range(n):
    m = int(input())
    if m in arr:
        arr.pop(arr.index(m))
    else:
        arr.append(m)
print(len(arr))

Fixed submission:
# ABC073C - Write and Erase
import sys
input = sys.stdin.readline

n = int(input())
arr = set()
for _ in range(n):
    m = int(input())
    if m in arr:
        arr.remove(m)
    else:
        arr.add(m)
print(len(arr))

Buggy python submission (verdict: Time Limit Exceeded):
# ABC073C - Write and Erase
import sys
input = sys.stdin.readline

n = int(input())
arr = []
for _ in range(n):
    m = int(input())
    if m in arr:
        arr.pop(arr.index(m))
    else:
        arr.append(m)
print(len(arr))

Fixed submission:
# ABC073C - Write and Erase
import sys
input = sys.stdin.readline

n = int(input())
arr = set()
for _ in range(n):
    m = int(input())
    if m in arr:
        arr.remove(m)
    else:
        arr.add(m)
print(len(arr))