matrix det

def det(matrix):
    n = len(matrix)

    def add_line(index1, index2, k): # matrix[index1] - matrix[index2]*k
        for i in range(n):
            matrix[index1][i]+=matrix[index2][i]*k

    for i in range(n):
        first_index = -1;
        for j in range(i,n):
            if(matrix[i][j]!=0):
                first_index = j;
                break;

        if first_index==-1:
            return 0

        if first_index>i:
            add_line(i,first_index,1)

        for j in range(i+1, n):
            if(matrix[j][i]!=0):
                add_line(j,i,-matrix[j][i]/matrix[i][i])

    ans = 1
    for i in range(n):
        ans*=matrix[i][i]
    return ans


dimCorrect = False
input_dim = 0
while True:
    print("Введите размерность матрицы")
    input_dim = input()
    try:
        input_dim = int(input_dim)
        if input_dim>0:
            break
    except Exception as e:
        continue
    print("Ошибка")

matrix = [0 for _ in range(input_dim)]
for i in range(input_dim):
    input_line = []
    while True:
        print("Введите ",int(i+1)," строку матрицы")
        try:
            input_line = list(map(float,input().split()))
            if len(input_line) == input_dim:
                lineCorrect = True
                break
        except Exception as e:
            continue
        print("Ошибка")
    matrix[i] = input_line

print("Определитель матрицы равен: ", det(matrix))