Problem:
Score : 300 points

Problem Statement

Sitting in a station waiting room, Joisino is gazing at her train ticket.

The ticket is numbered with four digits A, B, C and D in this order, each between 0 and 9 (inclusive).

In the formula A op1 B op2 C op3 D = 7, replace each of the symbols op1, op2 and op3 with + or - so that the formula holds.

The given input guarantees that there is a solution. If there are multiple solutions, any of them will be accepted.

Constraints

0≤A,B,C,D≤9

All input values are integers.

It is guaranteed that there is a solution.

Input

Input is given from Standard Input in the following format:

ABCD

Output

Print the formula you made, including the part =7.

Use the signs + and -.

Do not print a space between a digit and a sign.

Sample Input 1

1222

Sample Output 1

1+2+2+2=7

This is the only valid solution.

Sample Input 2

0290

Sample Output 2

0-2+9+0=7

0 - 2 + 9 - 0 = 7 is also a valid solution.

Sample Input 3

3242

Sample Output 3

3+2+4-2=7

Solution in Python (3.4.3) (judge verdict: Accepted)


def conv_bin(i, digit):
    if i & 1 << digit:
        return "+"
    else:
        return "-"


if __name__ == "__main__":
    abcd = input()
    bin_pattern_digit = len(abcd) - 1

    for i in range(1 << bin_pattern_digit):
        # 初期値:一番左の桁の値。
        result = int(abcd[0:1])
        for j in range(bin_pattern_digit):
            # +を入れた場合
            # 例：1234のパターン1「+」2の場合：i=0の時に+2(abcd[1:2])する必要がある。
            #                 3「-」4の場合：i=2の時に-4(abcd[3:4])する必要がある。
            if i & 1 << (bin_pattern_digit - j -1 ):
                # result += int(abcd[j + 1:j + 2])
                result += int(abcd[j + 1])
            # -を入れた場合
            else:
                # result -= int(abcd[j + 1:j + 2])
                result -= int(abcd[j + 1])

        # 合計が7なら終了
        if result == 7:
            break

    # 注意：
    # bit変数(i)の結果を確認する場合、文字列とスライスの併用(str(bit(i[0:1])))は使えない。
    # 数値と同じで、先頭0は消される = 桁数が可変であるため。
    # i & 1 << 0  # 1桁目が真か確認。
    # i & 1 << 1  # 2桁目が真か確認。
    # -dev-
    print(abcd[0:1] + conv_bin(i, 2) + abcd[1:2] + conv_bin(i, 1) + abcd[2:3] + conv_bin(i, 0) + abcd[3:4] + "=7")