Buggy python submission (verdict: Time Limit Exceeded):
import bisect

N, M = map(int, input().split())
task = []
for i in range(N):
    a, b = map(int, input().split())
    task.append((a, b))

task.sort()

wa = []
ans = 0
j = 0
for i in range(M):
    while j < N and task[j][0] == i + 1:
        bisect.insort_right(wa, task[j][1])
        j += 1
    if wa:
        ans += wa[-1]
        del (wa[-1])

print(ans)


Fixed submission:
import bisect
import heapq

N, M = map(int, input().split())
task = []
for i in range(N):
    a, b = map(int, input().split())
    task.append((a, b))

task.sort()

wa = []
ans = 0
j = 0
for i in range(M):
    while j < N and task[j][0] == i + 1:
        heapq.heappush(wa,-task[j][1])
        j += 1
    if wa:
        ans -= heapq.heappop(wa)

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
import bisect

N, M = map(int, input().split())
task = []
for i in range(N):
    a, b = map(int, input().split())
    task.append((a, b))

task.sort()

wa = []
ans = 0
j = 0
for i in range(M):
    while j < N and task[j][0] == i + 1:
        bisect.insort_right(wa, task[j][1])
        j += 1
    if wa:
        ls = wa[-1]
        ans += ls
        del (wa[-1])

print(ans)


Fixed submission:
import bisect
import heapq

N, M = map(int, input().split())
task = []
for i in range(N):
    a, b = map(int, input().split())
    task.append((a, b))

task.sort()

wa = []
ans = 0
j = 0
for i in range(M):
    while j < N and task[j][0] == i + 1:
        heapq.heappush(wa,-task[j][1])
        j += 1
    if wa:
        ans -= heapq.heappop(wa)

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
N, M = map(int, input().split())
task = []
for i in range(N):
    a, b = map(int, input().split())
    task.append((a, b))

task.sort()

wa = []
ans = 0
j = 0
for i in range(M):
    while j < N and task[j][0] == i + 1:
        wa.append(task[j][1])
        j += 1
    if wa:
        ls = max(wa)
        ans += ls
        wa.remove(ls)

print(ans)


Fixed submission:
import bisect
import heapq

N, M = map(int, input().split())
task = []
for i in range(N):
    a, b = map(int, input().split())
    task.append((a, b))

task.sort()

wa = []
ans = 0
j = 0
for i in range(M):
    while j < N and task[j][0] == i + 1:
        heapq.heappush(wa,-task[j][1])
        j += 1
    if wa:
        ans -= heapq.heappop(wa)

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
N, M = map(int, input().split())
task = []
for i in range(N):
    a, b = map(int, input().split())
    task.append((a, b))

task.sort()

wa = [0] * (10**5+10)
ans = 0
j = 0
for i in range(M):
    while j < N and task[j][0] == i + 1:
        wa[task[j][1]] += 1
        j += 1
    if sum(wa):
        ls = [i for i, e in enumerate(wa) if e != 0][-1]
        ans += ls
        wa[ls] -= 1

print(ans)


Fixed submission:
import bisect
import heapq

N, M = map(int, input().split())
task = []
for i in range(N):
    a, b = map(int, input().split())
    task.append((a, b))

task.sort()

wa = []
ans = 0
j = 0
for i in range(M):
    while j < N and task[j][0] == i + 1:
        heapq.heappush(wa,-task[j][1])
        j += 1
    if wa:
        ans -= heapq.heappop(wa)

print(ans)