CF977A.Wrong Subtraction

Little girl Tanya is learning how to decrease a number by one, but she does it wrong with a number consisting of two or more digits. Tanya subtracts one from a number by the following algorithm:

• if the last digit of the number is non-zero, she decreases the number by one;
• if the last digit of the number is zero, she divides the number by 10 (i.e. removes the last digit).

You are given an integer number $n$ . Tanya will subtract one from it $k$ times. Your task is to print the result after all $k$ subtractions.

It is guaranteed that the result will be positive integer number.

The first line of the input contains two integer numbers $n$ and $k$ ( $2 \le n \le 10^9$ , $1 \le k \le 50$ ) — the number from which Tanya will subtract and the number of subtractions correspondingly.

Print one integer number — the result of the decreasing $n$ by one $k$ times.

It is guaranteed that the result will be positive integer number.

The first example corresponds to the following sequence: $512 \rightarrow 511 \rightarrow 510 \rightarrow 51 \rightarrow 50$ .