The number on the board

2000ms

262144K

Description:

Some natural number was written on the board. Its sum of digits was not less than k. But you were distracted a bit, and someone changed this number to n, replacing some digits with others. It's known that the length of the number didn't change.

You have to find the minimum number of digits in which these two numbers can differ.

Input:

The first line contains integer k (1 ≤ k ≤ 10⁹).

The second line contains integer n (1 ≤ n < 10¹⁰⁰⁰⁰⁰).

There are no leading zeros in n. It's guaranteed that this situation is possible.

Output:

Print the minimum number of digits in which the initial number and n can differ.

Sample Input:

3
11

Sample Output:

Sample Input:

3
99

Sample Output:

Note:

In the first example, the initial number could be 12.

In the second example the sum of the digits of n is not less than k. The initial number could be equal to n.

Informação

Provedor Codeforces

Código CF835B