Buggy python submission (verdict: Time Limit Exceeded):
import math
n, k = map(int, input().split())
# a = [int(x) for x in input().split()]
# f = [int(x) for x in input().split()]
a = list(map(int, input().split()))
f = list(map(int, input().split()))
a.sort()
f.sort(reverse=True)
lx = 0
rx = a[-1] * f[0]
for i in range(1000):
    if lx == rx:
        break
    cx = (lx + rx) // 2
    kk = 0
    for j in range(n):
        ta = a[j]
        y = (ta*f[j] - cx + f[j] -1) // f[j]
        kk += max(0, y)
    if kk <= k:
        rx = cx
    else:
        lx = cx
print(rx)

Fixed submission:
n, k = map(int, input().split())
# a = [int(x) for x in input().split()]
# f = [int(x) for x in input().split()]
a = list(map(int, input().split()))
f = list(map(int, input().split()))
a.sort()
f.sort(reverse=True)
lx = -1
rx = a[-1] * f[0]
while rx-lx>1 :
    cx = (lx + rx) // 2
    kk = 0
    for j in range(n):
        kk += max(0, a[j] - cx//f[j])
    if kk <= k:
        rx = cx
    else:
        lx = cx
print(rx)

Buggy python submission (verdict: Time Limit Exceeded):
import math
n, k = map(int, input().split())
a = [int(x) for x in input().split()]
f = [int(x) for x in input().split()]
a.sort()
f.sort(reverse=True)
lx = 0
rx = a[-1] * f[0]
for i in range(1000):
    if lx == rx:
        break
    cx = (lx + rx) // 2
    kk = 0
    for j in range(n):
        ta = a[j]
        y = (ta*f[j] - cx + f[j] -1) // f[j]
        kk += max(0, y)
    if kk <= k:
        rx = cx
    else:
        lx = cx
print(rx)

Fixed submission:
n, k = map(int, input().split())
# a = [int(x) for x in input().split()]
# f = [int(x) for x in input().split()]
a = list(map(int, input().split()))
f = list(map(int, input().split()))
a.sort()
f.sort(reverse=True)
lx = -1
rx = a[-1] * f[0]
while rx-lx>1 :
    cx = (lx + rx) // 2
    kk = 0
    for j in range(n):
        kk += max(0, a[j] - cx//f[j])
    if kk <= k:
        rx = cx
    else:
        lx = cx
print(rx)

Buggy python submission (verdict: Time Limit Exceeded):
import math
n, k = map(int, input().split())
a = [int(x) for x in input().split()]
f = [int(x) for x in input().split()]
a.sort()
f.sort(reverse=True)
lx = 0
rx = 10 ** 12
for i in range(1000):
    if lx == rx:
        break
    cx = (lx + rx) // 2
    kk = 0
    for j in range(n):
        ta = a[j]
        y = (ta*f[j] - cx + f[j] -1) // f[j]
        kk += max(0, y)
    if kk <= k:
        rx = cx
    else:
        lx = cx
print(rx)

Fixed submission:
n, k = map(int, input().split())
# a = [int(x) for x in input().split()]
# f = [int(x) for x in input().split()]
a = list(map(int, input().split()))
f = list(map(int, input().split()))
a.sort()
f.sort(reverse=True)
lx = -1
rx = a[-1] * f[0]
while rx-lx>1 :
    cx = (lx + rx) // 2
    kk = 0
    for j in range(n):
        kk += max(0, a[j] - cx//f[j])
    if kk <= k:
        rx = cx
    else:
        lx = cx
print(rx)

Buggy python submission (verdict: Time Limit Exceeded):
n, k = map(int, input().split())
a = [int(x) for x in input().split()]
f = [int(x) for x in input().split()]
a.sort()
f.sort(reverse=True)
lx = 0
rx = 10 ** 12
for i in range(1000):
    if lx == rx:
        break
    cx = (lx + rx) // 2
    kk = 0
    for j in range(n):
        ta = a[j]
        while(ta*f[j] > cx):
            ta -= 1
            kk += 1
    if kk <= k:
        rx = cx
    else:
        lx = cx
print(rx)

Fixed submission:
n, k = map(int, input().split())
# a = [int(x) for x in input().split()]
# f = [int(x) for x in input().split()]
a = list(map(int, input().split()))
f = list(map(int, input().split()))
a.sort()
f.sort(reverse=True)
lx = -1
rx = a[-1] * f[0]
while rx-lx>1 :
    cx = (lx + rx) // 2
    kk = 0
    for j in range(n):
        kk += max(0, a[j] - cx//f[j])
    if kk <= k:
        rx = cx
    else:
        lx = cx
print(rx)

Buggy python submission (verdict: Time Limit Exceeded):
n, k = map(int, input().split())
a = [int(x) for x in input().split()]
f = [int(x) for x in input().split()]
a.sort()
f.sort(reverse=True)
lx = 0
rx = 10 ** 12
for i in range(1000):
    if lx == rx:
        break
    cx = (lx + rx) // 2
    kk = 0
    for j in range(n):
        ta = a[j]
        while(ta*f[j] > cx):
            ta -= 1
            kk += 1
    if kk <= k:
        rx = cx
    else:
        lx = cx
print(rx)

Fixed submission:
n, k = map(int, input().split())
# a = [int(x) for x in input().split()]
# f = [int(x) for x in input().split()]
a = list(map(int, input().split()))
f = list(map(int, input().split()))
a.sort()
f.sort(reverse=True)
lx = -1
rx = a[-1] * f[0]
while rx-lx>1 :
    cx = (lx + rx) // 2
    kk = 0
    for j in range(n):
        kk += max(0, a[j] - cx//f[j])
    if kk <= k:
        rx = cx
    else:
        lx = cx
print(rx)