Problem:
Score : 300 points

Problem Statement

You are given a string S of length N consisting of A, C, G and T. Answer the following Q queries:

Query i (1 \leq i \leq Q): You will be given integers l_i and r_i (1 \leq l_i < r_i \leq N). Consider the substring of S starting at index l_i and ending at index r_i (both inclusive). In this string, how many times does AC occurs as a substring?

Notes

A substring of a string T is a string obtained by removing zero or more characters from the beginning and the end of T.

For example, the substrings of ATCODER include TCO, AT, CODER, ATCODER and (the empty string), but not AC.

Constraints

2 \leq N \leq 10^5

1 \leq Q \leq 10^5

S is a string of length N.

Each character in S is A, C, G or T.

1 \leq l_i < r_i \leq N

Input

Input is given from Standard Input in the following format:

N Q
S
l_1 r_1
:
l_Q r_Q

Output

Print Q lines. The i-th line should contain the answer to the i-th query.

Sample Input 1

8 3
ACACTACG
3 7
2 3
1 8

Sample Output 1

2
0
3

Query 1: the substring of S starting at index 3 and ending at index 7 is ACTAC. In this string, AC occurs twice as a substring.

Query 2: the substring of S starting at index 2 and ending at index 3 is CA. In this string, AC occurs zero times as a substring.

Query 3: the substring of S starting at index 1 and ending at index 8 is ACACTACG. In this string, AC occurs three times as a substring.

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;

namespace ABC122C
{
    class Input
    {
        /// <summary>
        /// 1行の入力を取得する
        /// </summary>
        /// <returns>文字列</returns>
        public void String(out string s)
        {
            s = Console.ReadLine();
        }

        /// <summary>
        /// 複数行の入力を取得
        /// </summary>
        /// <returns>文字列の配列</returns>
        public void String(long rowNumber, out string[] s)
        {
            s = new String[rowNumber];
            for (long i = 0; i < rowNumber; i++)
            {
                String(out s[i]);
            }
        }

        /// <summary>
        /// 1行の入力を取得
        /// </summary>
        /// <returns>int型の値</returns>
        public void Int(out int i)
        {
            string s;
            String(out s);
            i = int.Parse(s);
        }

        /// <summary>
        /// 1行の入力を取得
        /// </summary>
        /// <param name="a"></param>
        public void Long(out long a)
        {
            string s;
            String(out s);
            a = long.Parse(s);
        }

        /// <summary>
        /// 2つの整数が1行に書かれている入力を、2つのlongで受け取る
        /// </summary>
        /// <param name="a"></param>
        /// <param name="b"></param>
        public void Long(out long a, out long b)
        {
            long[] lArr;
            Long(out lArr);
            a = lArr[0];
            b = lArr[1];
        }

        /// <summary>
        /// 3つの整数が1行に書かれている入力を、3つのlongで受け取る
        /// </summary>
        /// <param name="a"></param>
        /// <param name="b"></param>
        /// <param name="c"></param>
        public void Long(out long a, out long b, out long c)
        {
            long[] lArr;
            Long(out lArr);
            a = lArr[0];
            b = lArr[1];
            c = lArr[2];
        }

        /// <summary>
        /// 4つの整数が1行に書かれている入力を、4つのlongで受け取る
        /// </summary>
        /// <param name="a"></param>
        /// <param name="b"></param>
        /// <param name="c"></param>
        /// <param name="d"></param>
        public void Long(out long a, out long b, out long c, out long d)
        {
            long[] lArr;
            Long(out lArr);
            a = lArr[0];
            b = lArr[1];
            c = lArr[2];
            d = lArr[3];
        }

        public void Long(out long[] lArr)
        {
            lArr = Split().Select(long.Parse).ToArray();
        }

        public void Long(long rowNumber, out long[] lArr)
        {
            lArr = new long[rowNumber];
            for (long i = 0; i < rowNumber; i++)
            {
                Long(out lArr[i]);
            }
        }

        /// <summary>
        /// 2つの整数が複数行に書かれている入力を、2つのlong[]で受け取る
        /// </summary>
        /// <param name="rowNumber"></param>
        /// <param name="a"></param>
        /// <param name="b"></param>
        public void Long(long rowNumber, out long[] a, out long[] b)
        {
            a = new long[rowNumber];
            b = new long[rowNumber];
            for (int i = 0; i < rowNumber; i++)
            {
                Long(out a[i], out b[i]);
            }
        }

        /// <summary>
        /// 3つの整数が複数行に書かれている入力を、3つのlong[]で受け取る
        /// </summary>
        /// <param name="rowNumber"></param>
        /// <param name="a"></param>
        /// <param name="b"></param>
        /// <param name="c"></param>
        public void Long(long rowNumber, out long[] a, out long[] b, out long[] c)
        {
            a = new long[rowNumber];
            b = new long[rowNumber];
            c = new long[rowNumber];
            for (int i = 0; i < rowNumber; i++)
            {
                Long(out a[i], out b[i], out c[i]);
            }
        }

        /// <summary>
        /// 4つの整数が複数行に書かれている入力を、4つのlong[]で受け取る
        /// </summary>
        /// <param name="rowNumber"></param>
        /// <param name="a"></param>
        /// <param name="b"></param>
        /// <param name="c"></param>
        /// <param name="d"></param>
        public void Long(long rowNumber, out long[] a, out long[] b, out long[] c, out long[] d)
        {
            a = new long[rowNumber];
            b = new long[rowNumber];
            c = new long[rowNumber];
            d = new long[rowNumber];
            for (int i = 0; i < rowNumber; i++)
            {
                Long(out a[i], out b[i], out c[i], out d[i]);
            }
        }


        /// <summary>
        /// 1行の入力を取得
        /// </summary>
        /// <returns>double型の値</returns>
        public void Double(out double d)
        {
            string s;
            String(out s);
            d = double.Parse(s);
        }

        /// <summary>
        /// 1行の入力を取得
        /// </summary>
        /// <returns>double型の配列</returns>
        public void Double(out double[] dArr)
        {
            dArr = Split().Select(double.Parse).ToArray();
        }

        private IEnumerable<string> Split()
        {
            string s;
            String(out s);
            return s.Split(' ');
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            Solver solver = new Solver();
            solver.Solve();
        }
    }

    class Solver
    {
        public Solver()
        {
            Input input = new Input();
            input.Long(out N, out Q);
            input.String(out S);
            input.Long(Q, out l, out r);
        }

        private long N;
        private long Q;
        private string S;
        private long[] l;
        private long[] r;

        public void Solve()
        {
            long[] sum = new long[N + 1];

            bool a = false;
            for (int i = 0; i < N; i++)
            {
                sum[i + 1] = sum[i];
                
                if (a && S[i] == 'C')
                {
                    sum[i + 1]++;
                }

                a = S[i] == 'A';
            }

            for (long i = 0; i < Q; i++)
            {
                Console.WriteLine(sum[r[i]] - sum[l[i]]);
            }
        }
    }
}