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#include<bits/stdc++.h>
#define int long long
using namespace std;

constexpr int mod = 1e9 + 7;
constexpr int MAXN = 2e5 + 7;

int dp[MAXN][3];
int pow2[MAXN];

void count_pow2(int n)
{
    pow2[0] = 1;
    for (int i = 1; i <= n; i++)
        pow2[i] = (pow2[i - 1] << 1) % mod;
}

void count_dp(int n)
{
    dp[0][0] = 1;
    dp[0][1] = 0;
    dp[0][2] = 0;

    for (int i = 1; i <= n; i++){
        for (int r = 0; r < 3; r++){
            dp[i][r] = (pow2[i - 1] - dp[i - 1][(r + 1) % 3] + mod) % mod;
        }
    }
}

int get_rot(int n_rot, int num_red)
{
    num_red %= 3;
    return (n_rot - num_red + 3) % 3; 
}

int32_t main()
{
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    int n, q;
    string s;
    cin >> n >> q >> s;

    const int n_rot = 2 - ((n - 1) % 3);
    const bool ignore = (n == 1) || (n % 2 == 0);

    count_pow2(n + 5);
    count_dp(n);    

    int cantbe101 = 0;
    int cantbe010 = 0;

    int num_red = 0;
    int num_blue = 0;

    for (int i = 0; i < n; i++)
    {
        if (s[i] == 'N') {
            num_blue++;
            continue;
        }

        int curr = (s[i] == 'C');

        num_red += curr;
        if ((curr + i) % 2 == 1)
            cantbe010++;
        else
            cantbe101++;
    }
    
    int res = (pow2[num_blue] - dp[num_blue][get_rot(n_rot, num_red)] + mod) % mod;
    if (!ignore && !cantbe010) res--;
    if (!ignore && !cantbe101) res--;
    res = (res + mod) % mod;
    cout << res << "\n";

    for (int i = 1; i <= q; i++)
    {
        int where;
        char what;
        cin >> where >> what;
        where--;


        if (s[where] == 'N') num_blue--;
        else 
        {
            int curr = (s[where] == 'C');

            num_red -= curr;
            if ((curr + where) % 2 == 1)
                cantbe010--;
            else
                cantbe101--;
        }

        if (what == 'N') num_blue++;
        else 
        {
            int curr = (what == 'C');

            num_red += curr;
            if ((curr + where) % 2 == 1)
                cantbe010++;
            else
                cantbe101++;
        }

        s[where] = what;
        
        res = (pow2[num_blue] - dp[num_blue][get_rot(n_rot, num_red)] + mod) % mod;
        if (!ignore && !cantbe010) res--;
        if (!ignore && !cantbe101) res--;
        res = (res + mod) % mod;
        cout << res << "\n";
    }
    return 0;
}