William the Vigilant

Description:

Input:

The first line contains two integers $$$n$$$ and $$$q$$$ $$$(1 \le n, q \le 10^5)$$$, the length of the string and the number of queries, respectively.

The second line contains the string $$$s$$$, consisting of characters "a", "b" and "c".

Each of the next $$$q$$$ lines contains an integer $$$i$$$ and character $$$c$$$ $$$(1 \le i \le n)$$$, index and the value of the new item in the string, respectively. It is guaranteed that character's $$$c$$$ value is "a", "b" or "c".

Output:

For each query output the minimal number of characters that would have to be replaced so that the string doesn't contain "abc" as a substring.

Sample Input:

9 10
abcabcabc
1 a
1 b
2 c
3 a
4 b
5 c
8 a
9 b
1 c
4 a

Sample Output:

3
2
2
2
1
2
1
1
1
0

Note:

Let's consider the state of the string after each query:

1. $$$s =$$$ "abcabcabc". In this case $$$3$$$ replacements can be performed to get, for instance, string $$$s =$$$ "bbcaccabb". This string does not contain "abc" as a substring.
2. $$$s =$$$ "bbcabcabc". In this case $$$2$$$ replacements can be performed to get, for instance, string $$$s =$$$ "bbcbbcbbc". This string does not contain "abc" as a substring.
3. $$$s =$$$ "bccabcabc". In this case $$$2$$$ replacements can be performed to get, for instance, string $$$s =$$$ "bccbbcbbc". This string does not contain "abc" as a substring.
4. $$$s =$$$ "bcaabcabc". In this case $$$2$$$ replacements can be performed to get, for instance, string $$$s =$$$ "bcabbcbbc". This string does not contain "abc" as a substring.
5. $$$s =$$$ "bcabbcabc". In this case $$$1$$$ replacements can be performed to get, for instance, string $$$s =$$$ "bcabbcabb". This string does not contain "abc" as a substring.
6. $$$s =$$$ "bcabccabc". In this case $$$2$$$ replacements can be performed to get, for instance, string $$$s =$$$ "bcabbcabb". This string does not contain "abc" as a substring.
7. $$$s =$$$ "bcabccaac". In this case $$$1$$$ replacements can be performed to get, for instance, string $$$s =$$$ "bcabbcaac". This string does not contain "abc" as a substring.
8. $$$s =$$$ "bcabccaab". In this case $$$1$$$ replacements can be performed to get, for instance, string $$$s =$$$ "bcabbcaab". This string does not contain "abc" as a substring.
9. $$$s =$$$ "ccabccaab". In this case $$$1$$$ replacements can be performed to get, for instance, string $$$s =$$$ "ccabbcaab". This string does not contain "abc" as a substring.
10. $$$s =$$$ "ccaaccaab". In this case the string does not contain "abc" as a substring and no replacements are needed.