Buggy python submission (verdict: Time Limit Exceeded):
import math
import copy
import sys
import fractions
import numpy as np
from functools import reduce
import statistics
import heapq

input = sys.stdin.readline
sys.setrecursionlimit(10**6)

# ===FUNCTION===

def getInputInt():
    inputNum = int(input())
    return inputNum


def getInputListInt():
    outputData = []
    inputData = input().split()
    outputData = [int(n) for n in inputData]

    return outputData


def getSomeInputInt(n):
    outputDataList = []
    for i in range(n):
        inputData = int(input())
        outputDataList.append(inputData)

    return outputDataList


def getSomeInputListInt(n):
    inputDataList = []
    outputDataList = []
    for i in range(n):
        inputData = input().split()
        inputDataList = [int(n) for n in inputData]
        outputDataList.append(inputDataList)

    return outputDataList


# ===CODE===

n, m = map(int, input().split())
data = getSomeInputListInt(n)

data_list = [[0] for _ in range(m)]

for i in range(n):
    if data[i][0]-1 < m:
        data_list[data[i][0]-1].append(-data[i][1])

heap_list = []
heapq.heapify(heap_list)

ans = 0
for i in range(0, m):
    heap_list.extend(data_list[i])
    heapq.heapify(heap_list)
    a = heapq.heappop(heap_list)
    ans += a

print(-ans)

Fixed submission:
import math
import copy
import sys
import fractions
import numpy as np
from functools import reduce
import statistics
import heapq

input = sys.stdin.readline
sys.setrecursionlimit(10**6)

# ===FUNCTION===

def getInputInt():
    inputNum = int(input())
    return inputNum


def getInputListInt():
    outputData = []
    inputData = input().split()
    outputData = [int(n) for n in inputData]

    return outputData


def getSomeInputInt(n):
    outputDataList = []
    for i in range(n):
        inputData = int(input())
        outputDataList.append(inputData)

    return outputDataList


def getSomeInputListInt(n):
    inputDataList = []
    outputDataList = []
    for i in range(n):
        inputData = input().split()
        inputDataList = [int(n) for n in inputData]
        outputDataList.append(inputDataList)

    return outputDataList


# ===CODE===

n, m = map(int, input().split())
data = getSomeInputListInt(n)

data_list = [[0] for _ in range(m)]

for i in range(n):
    if data[i][0]-1 < m:
        data_list[data[i][0]-1].append(-data[i][1])

heap_list = []
heapq.heapify(heap_list)
# heapq.heapify(data_list)

ans = 0
for j in range(m):
    for i in range(len(data_list[j])):
        heapq.heappush(heap_list, data_list[j][i])
    a = heapq.heappop(heap_list)
    ans += a

print(-ans)

Buggy python submission (verdict: Runtime Error):
import math
import copy
import sys
import fractions
import numpy as np
from functools import reduce
import statistics
import heapq

input = sys.stdin.readline
sys.setrecursionlimit(10**6)

# ===FUNCTION===

def getInputInt():
    inputNum = int(input())
    return inputNum


def getInputListInt():
    outputData = []
    inputData = input().split()
    outputData = [int(n) for n in inputData]

    return outputData


def getSomeInputInt(n):
    outputDataList = []
    for i in range(n):
        inputData = int(input())
        outputDataList.append(inputData)

    return outputDataList


def getSomeInputListInt(n):
    inputDataList = []
    outputDataList = []
    for i in range(n):
        inputData = input().split()
        inputDataList = [int(n) for n in inputData]
        outputDataList.append(inputDataList)

    return outputDataList


# ===CODE===

n, m = map(int, input().split())
data = getSomeInputListInt(n)

data_list = [[0] for _ in range(m)]

for i in range(n):
    if data[i][0]-1 < n:
        data_list[data[i][0]-1].append(-data[i][1])

heap_list = []
heapq.heapify(heap_list)

ans = 0
for i in range(0, m):
    heap_list.extend(data_list[i])
    heapq.heapify(heap_list)
    a = heapq.heappop(heap_list)
    ans += a

print(-ans)

Fixed submission:
import math
import copy
import sys
import fractions
import numpy as np
from functools import reduce
import statistics
import heapq

input = sys.stdin.readline
sys.setrecursionlimit(10**6)

# ===FUNCTION===

def getInputInt():
    inputNum = int(input())
    return inputNum


def getInputListInt():
    outputData = []
    inputData = input().split()
    outputData = [int(n) for n in inputData]

    return outputData


def getSomeInputInt(n):
    outputDataList = []
    for i in range(n):
        inputData = int(input())
        outputDataList.append(inputData)

    return outputDataList


def getSomeInputListInt(n):
    inputDataList = []
    outputDataList = []
    for i in range(n):
        inputData = input().split()
        inputDataList = [int(n) for n in inputData]
        outputDataList.append(inputDataList)

    return outputDataList


# ===CODE===

n, m = map(int, input().split())
data = getSomeInputListInt(n)

data_list = [[0] for _ in range(m)]

for i in range(n):
    if data[i][0]-1 < m:
        data_list[data[i][0]-1].append(-data[i][1])

heap_list = []
heapq.heapify(heap_list)
# heapq.heapify(data_list)

ans = 0
for j in range(m):
    for i in range(len(data_list[j])):
        heapq.heappush(heap_list, data_list[j][i])
    a = heapq.heappop(heap_list)
    ans += a

print(-ans)

Buggy python submission (verdict: Time Limit Exceeded):
import math
import copy
import sys
import fractions
import numpy as np
from functools import reduce
import statistics
input = sys.stdin.readline
sys.setrecursionlimit(10**6)

# ===FUNCTION===

def getInputInt():
    inputNum = int(input())
    return inputNum


def getInputListInt():
    outputData = []
    inputData = input().split()
    outputData = [int(n) for n in inputData]

    return outputData


def getSomeInputInt(n):
    outputDataList = []
    for i in range(n):
        inputData = int(input())
        outputDataList.append(inputData)

    return outputDataList


def getSomeInputListInt(n):
    inputDataList = []
    outputDataList = []
    for i in range(n):
        inputData = input().split()
        inputDataList = [int(n) for n in inputData]
        outputDataList.append(inputDataList)

    return outputDataList


# ===CODE===

n, m = map(int, input().split())
data = getSomeInputListInt(n)

ans = 0
for i in range(1, m+1):
    tmp = 0
    tmpidx = -1
    for j in range(len(data)-1, -1, -1):
        if data[j][0] <= i:
           if tmp < data[j][1]:
               tmp = data[j][1]
               tmpidx = j
    if tmpidx != -1:
        ans += tmp
        data[tmpidx][1] = 0

print(ans)

Fixed submission:
import math
import copy
import sys
import fractions
import numpy as np
from functools import reduce
import statistics
import heapq

input = sys.stdin.readline
sys.setrecursionlimit(10**6)

# ===FUNCTION===

def getInputInt():
    inputNum = int(input())
    return inputNum


def getInputListInt():
    outputData = []
    inputData = input().split()
    outputData = [int(n) for n in inputData]

    return outputData


def getSomeInputInt(n):
    outputDataList = []
    for i in range(n):
        inputData = int(input())
        outputDataList.append(inputData)

    return outputDataList


def getSomeInputListInt(n):
    inputDataList = []
    outputDataList = []
    for i in range(n):
        inputData = input().split()
        inputDataList = [int(n) for n in inputData]
        outputDataList.append(inputDataList)

    return outputDataList


# ===CODE===

n, m = map(int, input().split())
data = getSomeInputListInt(n)

data_list = [[0] for _ in range(m)]

for i in range(n):
    if data[i][0]-1 < m:
        data_list[data[i][0]-1].append(-data[i][1])

heap_list = []
heapq.heapify(heap_list)
# heapq.heapify(data_list)

ans = 0
for j in range(m):
    for i in range(len(data_list[j])):
        heapq.heappush(heap_list, data_list[j][i])
    a = heapq.heappop(heap_list)
    ans += a

print(-ans)

Buggy python submission (verdict: Time Limit Exceeded):
import math
import copy
import sys
import fractions
import numpy as np
from functools import reduce
import statistics
input = sys.stdin.readline
sys.setrecursionlimit(10**6)

# ===FUNCTION===

def getInputInt():
    inputNum = int(input())
    return inputNum


def getInputListInt():
    outputData = []
    inputData = input().split()
    outputData = [int(n) for n in inputData]

    return outputData


def getSomeInputInt(n):
    outputDataList = []
    for i in range(n):
        inputData = int(input())
        outputDataList.append(inputData)

    return outputDataList


def getSomeInputListInt(n):
    inputDataList = []
    outputDataList = []
    for i in range(n):
        inputData = input().split()
        inputDataList = [int(n) for n in inputData]
        outputDataList.append(inputDataList)

    return outputDataList


# ===CODE===

n, m = map(int, input().split())
data = getSomeInputListInt(n)

ans = 0
for i in range(1, m+1):
    tmp = 0
    tmpidx = -1
    for j in range(len(data)-1, -1, -1):
        if data[j][0] <= i:
           if tmp < data[j][1]:
               tmp = data[j][1]
               tmpidx = j
    if tmpidx != -1:
        ans += tmp
        del data[tmpidx]

print(ans)

Fixed submission:
import math
import copy
import sys
import fractions
import numpy as np
from functools import reduce
import statistics
import heapq

input = sys.stdin.readline
sys.setrecursionlimit(10**6)

# ===FUNCTION===

def getInputInt():
    inputNum = int(input())
    return inputNum


def getInputListInt():
    outputData = []
    inputData = input().split()
    outputData = [int(n) for n in inputData]

    return outputData


def getSomeInputInt(n):
    outputDataList = []
    for i in range(n):
        inputData = int(input())
        outputDataList.append(inputData)

    return outputDataList


def getSomeInputListInt(n):
    inputDataList = []
    outputDataList = []
    for i in range(n):
        inputData = input().split()
        inputDataList = [int(n) for n in inputData]
        outputDataList.append(inputDataList)

    return outputDataList


# ===CODE===

n, m = map(int, input().split())
data = getSomeInputListInt(n)

data_list = [[0] for _ in range(m)]

for i in range(n):
    if data[i][0]-1 < m:
        data_list[data[i][0]-1].append(-data[i][1])

heap_list = []
heapq.heapify(heap_list)
# heapq.heapify(data_list)

ans = 0
for j in range(m):
    for i in range(len(data_list[j])):
        heapq.heappush(heap_list, data_list[j][i])
    a = heapq.heappop(heap_list)
    ans += a

print(-ans)