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#include <vector>
#include <iostream>
#include <sstream>
#include <math.h>
#include <sys/time.h>
#include <cstdlib>
#include <algorithm>
#include <cassert>
#include <cstring>
#include <fstream>
#include <set>
#include <map>
#include <iomanip>
#include <queue>

#define FOR(i,a,b)  for(__typeof(b) i=(a);i<(b);++i)
#define REP(i,a)    FOR(i,0,a)
#define FOREACH(x,c)   for(__typeof(c.begin()) x=c.begin();x != c.end(); x++)
#define ALL(c)      c.begin(),c.end()
#define CLEAR(c)    memset(c,0,sizeof(c))
#define SIZE(c) (int) ((c).size())

#define PB          push_back
#define MP          make_pair
#define X           first
#define Y           second

#define ULL         unsigned long long
#define LL          long long
#define LD          long double
#define II         pair<int, int>
#define DD         pair<double, double>
#define FF          pair<float,float>

#define VC	    vector
#define VI          VC<int>
#define VVI         VC<VI>
#define VVVI        VC<VVI>
#define VD          VC<double>
#define VS          VC<string>
#define VII         VC<II>
#define VDD         VC<DD>
#define VFF         VC<FF>
#define VVD         VC<VD>
#define VVVD        VC<VVD>
#define VULL         VC<ULL>

#define DB(a)       cerr << #a << ": " << a << endl;

using namespace std;

template<class T> void print(VC < T > v) {cerr << "[";if (SIZE(v) != 0) cerr << v[0]; FOR(i, 1, SIZE(v)) cerr << "," << v[i]; cerr << "]\n";}
template<class T> string i2s(T &x) { ostringstream o; o << x; return o.str(); }
VS split(string &s, char c = ' ') {VS all; int p = 0, np; while (np = s.find(c, p), np >= 0) {all.PB(s.substr(p, np - p)); p = np + 1;} if (p < SIZE(s)) all.PB(s.substr(p)); return all;}

int MOD = 1000000007;

int main(int argc, char *argv[]){
    int N, Q;
    cin >> N >> Q;
    string s;
    cin >> s;

    // binom
    int bin[N+1][3];
    bin[0][0] = 1;
    bin[0][1] = 0;
    bin[0][2] = 0;
    REP(i,N){
        bin[i+1][0] = (bin[i][1] + bin[i][2])%MOD;
        bin[i+1][1] = (bin[i][0] + bin[i][2])%MOD;
        bin[i+1][2] = (bin[i][0] + bin[i][1])%MOD;
    }
    int R[2] = {0,0}, G[2] = {0,0};
    
    REP(i,N){
        if (s[i] == 'C')
            R[i%2]++;
        else if (s[i] == 'Z')
            G[i%2]++;
    }

    int cnt = 0;
    REP(i,Q+1){
        int diff = (3*N + R[0] + R[1] - G[0] - G[1])%3;
        int B = N-R[0]-R[1]-G[0]-G[1];
        //cout << "FSDFSD " << B << " " << diff << endl;
        cnt = (bin[B][(diff+1)%3] + bin[B][(diff+2)%3])%MOD;
        if (N%2 != 0){
            cnt -= 2;
            if (R[0] != 0 || G[1] != 0)
                cnt++;
            if (R[1] != 0 || G[0] != 0)
                cnt++;
        }
        cnt = (cnt+MOD)%MOD;
        cout << cnt << endl;
        if (i == Q) break;
        int pos;
        char c;
        cin >> pos >> c;
        pos--;
        if (s[pos] == 'C')
            R[pos%2]--;
        else if (s[pos] == 'Z')
            G[pos%2]--;
        s[pos] = c;
        if (s[pos] == 'C')
            R[pos%2]++;
        else if (s[pos] == 'Z')
            G[pos%2]++;

    }
    return 0;
}