# Сортировка строки. В каждом слове содержится число.
# "is2 Thi1s T4est 3a"  -->  "Thi1s is2 3a T4est"
# "4of Fo1r pe6ople g3ood th5e the2"  -->  "Fo1r the2 g3ood 4of th5e pe6ople"

#
def order(sentence):
    my_list = sentence.split(' ')
    new_list = []
    print(my_list)
    for i in range(len(my_list)):
        for j in range(len(my_list)):
            if my_list[j].rfind(str(i+1)) != -1:
                new_list.append(my_list[j])

                
    return (' '.join(new_list))

# 
# def order(sentence):
    # return " ".join(sorted(sentence.split(), key=lambda x: int(filter(str.isdigit, x))))

# 
# def order(words):
#   return ' '.join(sorted(words.split(), key=lambda w:sorted(w)))


# print(order("is2 Thi1s T4est 3a"))


#
def find_even_index(arr):
    sum_left = 0
    sum_right = 0
    sum = []
    for i in range(len(arr)):
        for j in range(i):
            sum_left += arr[j]
        for k in range(len(arr) - 1,i ,-1):
            sum_right += arr[k]

        if sum_left == sum_right:
            sum.append(i)

        # print(f"Sum let: {sum_left} and sun right: {sum_right}")
        sum_left = sum_right = 0

    if len(sum) == 0:
        return -1
    else:
        sum.sort()
        return(sum[0])

'''
# Лучшее решение
def find_even_index(arr):
    for i in range(len(arr)):
        if sum(arr[:i]) == sum(arr[i+1:]):
            return i
    return -1
'''

# print(find_even_index([1,2,3,4,3,2,1]))
# print(find_even_index([1,2,3,4,5,6]))