Buggy python submission (verdict: Runtime Error):
import sys

readline = sys.stdin.buffer.readline
sys.setrecursionlimit(10**7)

import numpy as np

N = int(readline())
A = np.array(readline().split(), dtype=np.int64)
B = np.array(readline().split(), dtype=np.int64)

diff = A-B
lack = -diff[diff<0]
remain = diff[diff>0]

x = lack.sum()
remain.sort()
cum = remain[::-1].cumsum()

y = 0 if x == 0 else np.searchsorted(cum,x) + 1

answer = len(lack) + y if y <= len(remain) else -1
print(answer)

Fixed submission:
import sys
 
readline = sys.stdin.buffer.readline
sys.setrecursionlimit(10**7)
 
import numpy as np
 
N = int(readline())
A = np.array(readline().split(), dtype=np.int64)
B = np.array(readline().split(), dtype=np.int64)
 
diff = A-B
lack = -diff[diff<0]
remain = diff[diff>0]
 
x = lack.sum()
remain.sort()
cum = remain[::-1].cumsum()
 
y = 0 if x == 0 else np.searchsorted(cum,x) + 1
 
answer = len(lack) + y if y <= len(remain) else -1
print(answer)

Buggy python submission (verdict: Time Limit Exceeded):
import numpy as np
from numba import njit

n=int(input())
a=np.array(list(map(int, input().split())))
b=np.array(list(map(int, input().split())))

@njit
def func():
  if np.all(a>=b):
    print(0)
  elif np.sum(a)<np.sum(b):
    print(-1)
  else:
    temp_a = a[a-b<0]
    temp_b = b[a-b<0]
    sum_a = np.sum(temp_a)
    sum_b = np.sum(temp_b)
    ans = len(temp_a)

    if sum_a>=sum_b:
      print(ans)
    else:
      aa = a[a-b>=0]
      bb = b[a-b>=0]
      for _ in range(n-ans):
        index = np.argmax(aa-bb)
        sum_a += aa[index]
        sum_b += bb[index]
        ans += 1
        if sum_a>=sum_b:
          print(ans)
          break
        else:
          aa[index]=0
          bb[index]=0
          continue
func()

Fixed submission:
import sys
 
readline = sys.stdin.buffer.readline
sys.setrecursionlimit(10**7)
 
import numpy as np
 
N = int(readline())
A = np.array(readline().split(), dtype=np.int64)
B = np.array(readline().split(), dtype=np.int64)
 
diff = A-B
lack = -diff[diff<0]
remain = diff[diff>0]
 
x = lack.sum()
remain.sort()
cum = remain[::-1].cumsum()
 
y = 0 if x == 0 else np.searchsorted(cum,x) + 1
 
answer = len(lack) + y if y <= len(remain) else -1
print(answer)

Buggy python submission (verdict: Time Limit Exceeded):
import numpy as np

n=int(input())
a=np.array(list(map(int, input().split())))
b=np.array(list(map(int, input().split())))

if np.all(a>=b):
  print(0)
elif np.sum(a)<np.sum(b):
  print(-1)
else:
  temp_a = a[a-b<0]
  temp_b = b[a-b<0]
  sum_a = np.sum(temp_a)
  sum_b = np.sum(temp_b)
  ans = len(temp_a)

  if sum_a>=sum_b:
    print(ans)
  else:
    aa = a[a-b>=0]
    bb = b[a-b>=0]
    for _ in range(n-ans):
      index = np.argmax(aa-bb)
      sum_a += aa[index]
      sum_b += bb[index]
      ans += 1
      if sum_a>=sum_b:
        print(ans)
        exit()
      else:
        aa[index]=0
        bb[index]=0
        continue

Fixed submission:
import sys
 
readline = sys.stdin.buffer.readline
sys.setrecursionlimit(10**7)
 
import numpy as np
 
N = int(readline())
A = np.array(readline().split(), dtype=np.int64)
B = np.array(readline().split(), dtype=np.int64)
 
diff = A-B
lack = -diff[diff<0]
remain = diff[diff>0]
 
x = lack.sum()
remain.sort()
cum = remain[::-1].cumsum()
 
y = 0 if x == 0 else np.searchsorted(cum,x) + 1
 
answer = len(lack) + y if y <= len(remain) else -1
print(answer)