Polycarp likes numbers that are divisible by 3.

He has a huge number $s$. Polycarp wants to cut from it the maximum number of numbers that are divisible by $3$. To do this, he makes an arbitrary number of vertical cuts between pairs of adjacent digits. As a result, after $m$ such cuts, there will be $m+1$ parts in total. Polycarp analyzes each of the obtained numbers and finds the number of those that are divisible by $3$.

For example, if the original number is $s=3121$, then Polycarp can cut it into three parts with two cuts: $3|1|21$. As a result, he will get two numbers that are divisible by $3$.

Polycarp can make an arbitrary number of vertical cuts, where each cut is made between a pair of adjacent digits. The resulting numbers cannot contain extra leading zeroes (that is, the number can begin with 0 if and only if this number is exactly one character '0'). For example, 007, 01 and 00099 are not valid numbers, but 90, 0 and 10001 are valid.

What is the maximum number of numbers divisible by $3$ that Polycarp can obtain?
The first line of the input contains a positive integer $s$. The number of digits of the number $s$ is between $1$ and $2\cdot10^5$, inclusive. The first (leftmost) digit is not equal to 0.
3121
2
6
1
1000000000000000000000000000000000
33
201920181
4
4
0
10
1
11
0
12
1
13
1
31
1
14139582796
6
1670000
5
604500
5
40041
2
10000170
5
s = input().strip()

# Count the number of digits with each remainder when divided by 3
counts = [0, 0, 0]
total_sum = 0
for digit in s:
    num = int(digit)
    counts[num % 3] += 1
    total_sum += num

# Calculate the maximum number of numbers divisible by 3 that Polycarp can obtain
operations = 0

# Case 1: The total sum is divisible by 3
if total_sum % 3 == 0:
    operations = 0

# Case 2: The total sum is not divisible by 3
else:
    # Case 2.1: There are digits with remainder 1 and remainder 2
    if counts[1] != 0 and counts[2] != 0:
        operations = 1

    # Case 2.2: There are only digits with remainder 1 or only digits with remainder 2
    elif counts[1] != 0 or counts[2] != 0:
        operations = 2

# Print the maximum number of numbers divisible by 3 that Polycarp can obtain
print(operations)