Buggy python submission (verdict: Time Limit Exceeded):
import numpy as np
def main():
    listA=[]
    while True:
        try:
            listA.append(list(map(int,input().split())))
        except:
            break;
    N = listA[0][0]
    A = listA[1]
    B = listA[2]

    if sum(A) < sum(B):
        print(-1)
        return
    C = []

    C = np.array(A) - np.array(B)
    C = C.tolist()
    change_list = [i for i in C if i < 0]
    change_count = len(change_list)
    if change_count == 0:
        print(0)
        return
    max_ = 0
    while True:
        change_count += 1
        max_ += max(C)
        if abs(sum(change_list)) < max_:
            break
        C[C.index(max(C))] = 0

    print(change_count)

if __name__ == '__main__':
    main()

Fixed submission:
def solve():
    N = int(input())
    A = list(map(int, input().split()))
    B = list(map(int, input().split()))

    if sum(A) < sum(B):
        return -1

    C = [a-b for a,b in zip(A,B)]
    plus = [x for x in C if x > 0]
    minus = [x for x in C if x < 0]
    change = sum(minus)
    count = 0
    if change == 0:
        return 0

    for i in sorted(plus,reverse=True):
        if change >= 0:
            break
        change += i
        count += 1
    return count + len(minus)

print(solve())

Buggy python submission (verdict: Time Limit Exceeded):
listA=[]
while True:
    try:
        listA.append(list(map(int,input().split())))
    except:
        break;
N = listA[0][0]
A = listA[1]
B = listA[2]

if sum(A) < sum(B):
    print(-1)
    exit()
C = []
for i in range(len(A)):
    num = A[i] - B[i]
    C.append(num)
change_list = [i for i in C if i < 0]
change_count = len(change_list)
if change_count == 0:
    print(0)
    exit()
max_ = 0
while True:
    change_count += 1
    max_ += max(C)
    if abs(sum(change_list)) < max_:
        break
    C[C.index(max(C))] = 0

print(change_count)

Fixed submission:
def solve():
    N = int(input())
    A = list(map(int, input().split()))
    B = list(map(int, input().split()))

    if sum(A) < sum(B):
        return -1

    C = [a-b for a,b in zip(A,B)]
    plus = [x for x in C if x > 0]
    minus = [x for x in C if x < 0]
    change = sum(minus)
    count = 0
    if change == 0:
        return 0

    for i in sorted(plus,reverse=True):
        if change >= 0:
            break
        change += i
        count += 1
    return count + len(minus)

print(solve())

Buggy python submission (verdict: Time Limit Exceeded):

# ===== Main ==== #
def main():
    # =Input Space = #
    listA=[]
    while True:
        try:
            listA.append(list(map(int,input().split())))
        except:
            break;
    N = listA[0][0]
    A = listA[1]
    B = listA[2]

    if sum(A) < sum(B):
        print(-1)
        return 0
    C = []
    for i in range(len(A)):
        num = A[i] - B[i]
        C.append(num)
    D = C.copy()
    change_list = [i for i in C if i < 0]
    change_count = len(change_list)

    while True:
        if len([i for i in change_list if i < 0]) == 0:
            break
        max_ = max(C)
        max_index = C.index(max_)
        count = -1
        for i in change_list:
            count += 1
            if i < 0:
                if max_ <= abs(i):
                    change_list[count] += max_
                    max_ = 0
                    break
                else:
                    change_list[count] = 0
                    max_ -= abs(i)
        C[max_index] = max_
        change_count += 1

    print(change_count)


if __name__ == '__main__':
    main()


Fixed submission:
def solve():
    N = int(input())
    A = list(map(int, input().split()))
    B = list(map(int, input().split()))

    if sum(A) < sum(B):
        return -1

    C = [a-b for a,b in zip(A,B)]
    plus = [x for x in C if x > 0]
    minus = [x for x in C if x < 0]
    change = sum(minus)
    count = 0
    if change == 0:
        return 0

    for i in sorted(plus,reverse=True):
        if change >= 0:
            break
        change += i
        count += 1
    return count + len(minus)

print(solve())

Buggy python submission (verdict: Time Limit Exceeded):

# ===== Main ==== #
def main():
    # =Input Space = #
    listA=[]
    while True:
        try:
            listA.append(list(map(int,input().split())))
        except:
            break;
    N = listA[0][0]
    A = listA[1]
    B = listA[2]

    if sum(A) < sum(B):
        print(-1)
        return 0
    C = []
    for i in range(len(A)):
        num = A[i] - B[i]
        C.append(num)
    D = C.copy()

    while True:
        if len([i for i in C if i < 0]) == 0:
            break
        max_ = max(C)
        max_index = C.index(max_)
        count = -1
        for i in C:
            count += 1
            if i < 0:
                if max_ <= abs(i):
                    C[count] += max_
                    max_ = 0
                    break
                else:
                    C[count] = 0
                    max_ -= abs(i)
        C[max_index] = max_

    count = 0
    for i in range(len(C)):
        if D[i] != C[i]:
            count += 1
    print(count)


if __name__ == '__main__':
    main()

Fixed submission:
def solve():
    N = int(input())
    A = list(map(int, input().split()))
    B = list(map(int, input().split()))

    if sum(A) < sum(B):
        return -1

    C = [a-b for a,b in zip(A,B)]
    plus = [x for x in C if x > 0]
    minus = [x for x in C if x < 0]
    change = sum(minus)
    count = 0
    if change == 0:
        return 0

    for i in sorted(plus,reverse=True):
        if change >= 0:
            break
        change += i
        count += 1
    return count + len(minus)

print(solve())