9661: ABC182 —— C - To 3
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Description
Given is a positive integer $N$, where none of the digits is $0$.
Let $k$ be the number of digits in $N$. We want to make a multiple of $3$ by erasing at least $0$ and at most $k-1$ digits from $N$ and concatenating the remaining digits without changing the order.
Determine whether it is possible to make a multiple of $3$ in this way. If it is possible, find the minimum number of digits that must be erased to make such a number.
Let $k$ be the number of digits in $N$. We want to make a multiple of $3$ by erasing at least $0$ and at most $k-1$ digits from $N$ and concatenating the remaining digits without changing the order.
Determine whether it is possible to make a multiple of $3$ in this way. If it is possible, find the minimum number of digits that must be erased to make such a number.
Input
Input is given from Standard Input in the following format:
```
$N$
```
```
$N$
```
Output
If it is impossible to make a multiple of $3$, print `-1`; otherwise, print the minimum number of digits that must be erased to make such a number.
Constraints
- $1 \le N \lt 10^{18}$
- None of the digits in $N$ is $0$.
- None of the digits in $N$ is $0$.
Sample 1 Input
35
Sample 1 Output
1
By erasing the 5, we get the number 3, which is a multiple of 3. Here we erased the minimum possible number of digits - 1.
Sample 2 Input
369
Sample 2 Output
0
Note that we can choose to erase no digit.
Sample 3 Input
6227384
Sample 3 Output
1
For example, by erasing the 8, we get the number 622734, which is a multiple of 3.
11
-1
Note that we must erase at least 0 and at most k−1 digits, where k is the number of digits in N, so we cannot erase all the digits.
In this case, it is impossible to make a multiple of 3 in the way described in the problem statement, so we should print -1.
In this case, it is impossible to make a multiple of 3 in the way described in the problem statement, so we should print -1.