Buggy python submission (verdict: Time Limit Exceeded):
import sys
import bisect
input = sys.stdin.readline
def main():
    n,k = map(int,input().split())
    a = list(map(int,input().split()))
    f = list(map(int,input().split()))
    if sum(a)<=k:
        print(0)
    else:
        a.sort()
        f.sort(reverse=True)
        mul=[]
        for i in range(n):
            mul.append([a[i]*f[i],a[i]])
        mul.sort(reverse=True)
        for _ in range(k):
            mul[0][0]-=(mul[0][0]//mul[0][1])
            mul[0][1]-=1
            if mul[0][0]<mul[1][0]:
                mul.sort(reverse=True)
        print(mul[0][0])
main()

Fixed submission:
def main():
    # x,y = map(int,input().split())           x=1,y=2
    # a = input().split()                      a=['1','2','3',...,'n']
    # a = list(map(int,input().split()))       a=[1,2,3,4,5,...,n]
    # li = input().split('T')	              FFFTFTTFF => li=['FFF', 'F', '', 'FF']
    # 複数行の「1 2 3 4」型の入力を一配列に
    # x = sorted([list(map(int, input().split())) for _ in range(n)])
    # ソート x.sort(key=lambda y:y[1])
    # [chr(i) for i in range(97, 97+26)] 英語小文字リスト
    # [chr(i) for i in range(65, 65+26)] 英語大文字リスト atcoder
    # ord(c) chr(2) alphabet <=> number
    n,k = map(int,input().split())
    a = list(map(int,input().split()))
    f = list(map(int,input().split()))
    a.sort()
    f.sort(reverse=True)
    ok = 10**12
    ng=-1

    while ok-ng>1:
        mid=(ok+ng)//2
        cnt=0
        for x,y in enumerate(a):
            cnt+=max(0,y-mid//f[x])
        if cnt>k:
            ng=mid
        else:
            ok=mid
    print(ok)
main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys
import bisect
input = sys.stdin.readline
def main():
    n,k = map(int,input().split())
    a = list(map(int,input().split()))
    f = list(map(int,input().split()))
    if sum(a)<=k:
        print(0)
    else:
        a.sort()
        f.sort(reverse=True)
        mul=[]
        for i in range(n):
            mul.append([a[i]*f[i],a[i]])
        mul.sort(reverse=True)
        top=0
        for _ in range(k):
            mul[top][0]-=(mul[top][0]//mul[top][1])
            mul[top][1]-=1
            index=1
            if mul[top][0]<mul[top+1][0]:
                mul.append([0,0])
            while mul[top][0]<mul[top+1][0] and mul[top][0]>=mul[-1-index][0]:
                mul[-index]=mul[-1-index]
                index+=1
            if mul[top][0]<mul[top+1][0]:
                mul[-index]=mul[top]
                mul[top]=[0,0]
                top+=1
        print(mul[top][0])

main()

Fixed submission:
def main():
    # x,y = map(int,input().split())           x=1,y=2
    # a = input().split()                      a=['1','2','3',...,'n']
    # a = list(map(int,input().split()))       a=[1,2,3,4,5,...,n]
    # li = input().split('T')	              FFFTFTTFF => li=['FFF', 'F', '', 'FF']
    # 複数行の「1 2 3 4」型の入力を一配列に
    # x = sorted([list(map(int, input().split())) for _ in range(n)])
    # ソート x.sort(key=lambda y:y[1])
    # [chr(i) for i in range(97, 97+26)] 英語小文字リスト
    # [chr(i) for i in range(65, 65+26)] 英語大文字リスト atcoder
    # ord(c) chr(2) alphabet <=> number
    n,k = map(int,input().split())
    a = list(map(int,input().split()))
    f = list(map(int,input().split()))
    a.sort()
    f.sort(reverse=True)
    ok = 10**12
    ng=-1

    while ok-ng>1:
        mid=(ok+ng)//2
        cnt=0
        for x,y in enumerate(a):
            cnt+=max(0,y-mid//f[x])
        if cnt>k:
            ng=mid
        else:
            ok=mid
    print(ok)
main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys
import bisect
input = sys.stdin.readline
def main():
    n,k = map(int,input().split())
    a = list(map(int,input().split()))
    f = list(map(int,input().split()))
    if sum(a)<=k:
        print(0)
    else:
        a.sort()
        f.sort(reverse=True)
        mul=[]
        for i in range(n):
            mul.append([a[i]*f[i],a[i]])
        mul.sort(reverse=True)
        for _ in range(k):
            mul[0][0]-=(mul[0][0]//mul[0][1])
            mul[0][1]-=1
            mul.sort(reverse=True)
        print(mul[0][0])



main()

Fixed submission:
def main():
    # x,y = map(int,input().split())           x=1,y=2
    # a = input().split()                      a=['1','2','3',...,'n']
    # a = list(map(int,input().split()))       a=[1,2,3,4,5,...,n]
    # li = input().split('T')	              FFFTFTTFF => li=['FFF', 'F', '', 'FF']
    # 複数行の「1 2 3 4」型の入力を一配列に
    # x = sorted([list(map(int, input().split())) for _ in range(n)])
    # ソート x.sort(key=lambda y:y[1])
    # [chr(i) for i in range(97, 97+26)] 英語小文字リスト
    # [chr(i) for i in range(65, 65+26)] 英語大文字リスト atcoder
    # ord(c) chr(2) alphabet <=> number
    n,k = map(int,input().split())
    a = list(map(int,input().split()))
    f = list(map(int,input().split()))
    a.sort()
    f.sort(reverse=True)
    ok = 10**12
    ng=-1

    while ok-ng>1:
        mid=(ok+ng)//2
        cnt=0
        for x,y in enumerate(a):
            cnt+=max(0,y-mid//f[x])
        if cnt>k:
            ng=mid
        else:
            ok=mid
    print(ok)
main()