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// while (clock()<=69*CLOCKS_PER_SEC)
// #pragma comment(linker, "/stack:200000000")
// #pragma GCC optimize("O3")
// #pragma GCC target ("avx2")
// #pragma GCC optimize("Ofast")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
// #pragma GCC optimize("unroll-loops")

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace __gnu_pbds;
using namespace std;

template <typename T>
using ordered_set =
    tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

#define sim template <class c
#define ris return *this
#define dor > debug &operator<<
#define eni(x)                                                                    \
    sim > typename enable_if<sizeof dud<c>(0) x 1, debug &>::type operator<<(c i) \
    {
sim > struct rge {
    c b, e;
};
sim > rge<c> range(c i, c j) { return rge<c>{i, j}; }
sim > auto dud(c *x) -> decltype(cerr << *x, 0);
sim > char dud(...);
struct debug {
#ifdef XOX
    ~debug()
    {
        cerr << endl;
    }
    eni(!=) cerr << boolalpha << i;
    ris;
} eni(==) ris << range(begin(i), end(i));
}
sim, class b dor(pair<b, c> d)
{
    ris << "" << d.first << " --> " << d.second << "";
}
sim dor(rge<c> d)
{
    *this << "[";
    for (auto it = d.b; it != d.e; ++it)
        *this << ", " + 2 * (it == d.b) << *it;
    ris << "]";
}
#else
    sim dor(const c &)
    {
        ris;
    }
#endif
}
;
#define imie(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "

#ifdef XOX
#warning Times may differ!!!
#endif

#define endl '\n'
#define pb emplace_back
#define vt vector
#define rep(i, a, b) for (int i = a; i < (b); ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;

const int nax = 2000 * 1007, mod = 1e9 + 7;

struct mint {
    int v;
    mint() { v = 0; }
    mint(ll _v)
    {
        v = int((-mod < _v && _v < mod) ? _v : _v % mod);
        if (v < 0) v += mod;
    }
    friend bool operator==(const mint &a, const mint &b)
    {
        return a.v == b.v;
    }
    friend bool operator!=(const mint &a, const mint &b)
    {
        return !(a == b);
    }
    friend bool operator<(const mint &a, const mint &b)
    {
        return a.v < b.v;
    }
    mint &operator+=(const mint &m)
    {
        if ((v += m.v) >= mod) v -= mod;
        return *this;
    }
    mint &operator-=(const mint &m)
    {
        if ((v -= m.v) < 0) v += mod;
        return *this;
    }
    mint &operator*=(const mint &m)
    {
        v = (ll)v * m.v % mod;
        return *this;
    }
    mint &operator/=(const mint &m) { return (*this) *= inv(m); }
    friend mint pow(mint a, ll p)
    {
        mint ans = 1;
        assert(p >= 0);
        for (; p; p /= 2, a *= a)
            if (p & 1) ans *= a;
        return ans;
    }
    friend mint inv(const mint &a)
    {
        assert(a.v != 0);
        return pow(a, mod - 2);
    }
    mint operator-() const { return mint(-v); }
    mint &operator++() { return *this += 1; }
    mint &operator--() { return *this -= 1; }
    friend mint operator+(mint a, const mint &b) { return a += b; }
    friend mint operator-(mint a, const mint &b) { return a -= b; }
    friend mint operator*(mint a, const mint &b) { return a *= b; }
    friend mint operator/(mint a, const mint &b) { return a /= b; }
    friend std::istream &operator>>(std::istream &stream, mint &v)
    {
        ll s;
        stream >> s;
        v = mint(s);
        return stream;
    }
    friend std::ostream &operator<<(std::ostream &stream, const mint &v)
    {
        return stream << v.v;
    }
};

int lookup[3][6] = {{2, 1, -1, -2, -1, 1},
                    {-1, 1, 2, 1, -1, -2},
                    {-1, -2, -1, 1, 2, 1}};

int32_t main()
{
    cin.tie(0)->sync_with_stdio(0);
    int n, q;
    cin >> n >> q;
    string s;
    cin >> s;
    s = "#" + s;
    vector<vector<int>> licz(3, vector<int>(2));
    vector<mint> cache(n + 1);
    cache[0] = 1;
    for (int i = 1; i <= n; i++) {
        cache[i] = cache[i - 1] * 2;
    }
    for (int i = 1; i <= n; i++) {
        if (s[i] == 'C') {
            s[i] = 0;
        }
        else if (s[i] == 'Z') {
            s[i] = 1;
        }
        else {
            s[i] = 2;
        }
        licz[s[i]][i % 2]++;
    }
    auto sol = [&]() {
        auto m3 = [&](int x) {
            return (x % 3 + 3) % 3;
        };
        int dif = m3(licz[0][0] + licz[0][1] - licz[1][0] - licz[1][1]);
        int m = licz[2][0] + licz[2][1];
        int moj_x = m3(2 * (m - dif));
        auto wez = [&](int x) {
            return cache[m] - (cache[m] + lookup[x][m % 6]) * 333333336;
        };
        auto odj = [&]() {
            if (n == 1 || n % 2 == 0) {
                return 0;
            }
            return ((licz[0][0] + licz[1][1] + m) == n) + ((licz[0][1] + licz[1][0] + m) == n);
        };
        return wez(moj_x) - odj();
    };
    cout << sol() << endl;
    for (int i = 1; i <= q; i++) {
        int x;
        char z;
        cin >> x >> z;
        if (z == 'C') {
            z = 0;
        }
        else if (z == 'Z') {
            z = 1;
        }
        else {
            z = 2;
        }
        licz[s[x]][x % 2]--;
        s[x] = z;
        licz[s[x]][x % 2]++;
        cout << sol() << endl;
    }
}