求助，这段代码为什么会RE，想不明白

import sys
input = sys.stdin.readline
from sortedcontainers import SortedList

n, q = map(int, input().split())
a = list(map(int, input().split()))
st = SortedList(a)

for _ in range(q):
    opt, x = map(int, input().split())
    if opt == 1:
        if st.count(x):
            st.remove(x)
        else:
            print(-1)
            continue
    else:
        st.add(x)
    print(2*(st[-1]-st[0]))