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#include <iostream>
#include <string>
#include <algorithm>
#include <vector>

#define LL long long

using namespace std;

constexpr LL MOD = 1e9 + 7;

class SegmentTree
{
    int n;
    vector<vector<LL>> data;

public:

    SegmentTree(int n, int l, string &s) : n(n), data(vector<vector<LL>>(3, vector<LL>(n << 1)))
    {
        for (int i = 0; i < l; ++i)
        {
            if (s[i] == 'N')
            {
                data[0][n + i] = 1;
                data[1][n + i] = 1;
            }
            else if (s[i] == 'C') data[1][n + i] = 1;
            else data[0][n + i] = 1;
        }

        for (int v = n + l; v < (n << 1); ++v)
        {
            data[0][v] = 1;
        }

        for (int v = n - 1; v; --v)
        {
            data[0][v] = (data[0][v << 1] * data[0][v << 1 | 1]
                          + data[1][v << 1] * data[2][v << 1 | 1]
                          + data[2][v << 1] * data[1][v << 1 | 1]) % MOD;
            data[1][v] = (data[0][v << 1] * data[1][v << 1 | 1]
                          + data[1][v << 1] * data[0][v << 1 | 1]
                          + data[2][v << 1] * data[2][v << 1 | 1]) % MOD;
            data[2][v] = (data[2][v << 1] * data[0][v << 1 | 1]
                          + data[0][v << 1] * data[2][v << 1 | 1]
                          + data[1][v << 1] * data[1][v << 1 | 1]) % MOD;
        }
    }

    void update(int v, char c)
    {
        v += n;
        if (c == 'N')
        {
            data[0][v] = 1;
            data[1][v] = 1;
        }
        else if (c == 'C')
        {
            data[0][v] = 0;
            data[1][v] = 1;
        }
        else
        {
            data[0][v] = 1;
            data[1][v] = 0;
        }
        v >>= 1;

        while (v)
        {
            data[0][v] = (data[0][v << 1] * data[0][v << 1 | 1]
                          + data[1][v << 1] * data[2][v << 1 | 1]
                          + data[2][v << 1] * data[1][v << 1 | 1]) % MOD;
            data[1][v] = (data[0][v << 1] * data[1][v << 1 | 1]
                          + data[1][v << 1] * data[0][v << 1 | 1]
                          + data[2][v << 1] * data[2][v << 1 | 1]) % MOD;
            data[2][v] = (data[2][v << 1] * data[0][v << 1 | 1]
                          + data[0][v << 1] * data[2][v << 1 | 1]
                          + data[1][v << 1] * data[1][v << 1 | 1]) % MOD;
            v >>= 1;
        }
    }

    LL query(int r)
    {
        LL res = 0;
        for (int i = 0; i < 3; ++i)
        {
            if ((i + r) % 3) res += data[i][1];
            res %= MOD;
        }
        return res;
    }
};

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

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

    SegmentTree T(1 << 18, n, s);
    vector<int> cnt(4);
    for (int i = 0; i < n; ++i)
    {
        if (s[i] != 'N') ++cnt[2 * (s[i] == 'C') + (i % 2)];
    }

    LL res = T.query(n);
    if (!cnt[0] && !cnt[3]) --res;
    if (!cnt[1] && !cnt[2]) --res;
    if (res < 0) res += MOD;
    cout << res << "\n";

    int pos;
    char c;
    while (q--)
    {
        cin >> pos >> c;
        --pos;

        if (s[pos] != 'N') --cnt[2 * (s[pos] == 'C') + pos % 2];
        if (c != 'N') ++cnt[2 * (c == 'C') + pos % 2];
        s[pos] = c;
        T.update(pos, c);

        res = T.query(n);
        if (!cnt[0] && !cnt[3]) --res;
        if (!cnt[1] && !cnt[2]) --res;
        if (res < 0) res += MOD;
        cout << res << "\n";
    }
}