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#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod=1000000007;
const int N=200010;
ll pw2[N];
int a[N];
int tot=0;
int badA=0,badB=0;
int sum=0;
int n,q;
ll dp[N][3];
ll solve(){
    if (n==1){
        return pw2[tot];
    }
    ll res=0ll;

    if (tot==0){
        res=(sum!=0);
    } else {
        int cur=(sum+tot)%3;
        res=pw2[tot];
        cur=(3-cur)%3;
        res+=mod-dp[tot][cur];
        res%=mod;

    }
    if (badA==0 && n%2) res+=mod-1;
    if (badB==0 && n%2) res+=mod-1;
    return res%mod;
}
void upd(int pos,int x){
    sum+=3-a[pos];
    if (pos%2+1==a[pos]) badA--;
    if ((pos+1)%2+1==a[pos]) badB--;
    if (a[pos]==0) tot--;
    a[pos]=x;
    sum+=a[pos];
    if (pos%2+1==a[pos]) badA++;
    if ((pos+1)%2+1==a[pos]) badB++;
    if (a[pos]==0) tot++;
    sum%=3;
}
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cin>>n>>q;
    dp[0][0]=1;
    for (int i=0;i<n;i++){
        for (int j=0;j<3;j++){
            for (int t=0;t<2;t++){
                (dp[i+1][(j+t)%3]+=dp[i][j])%=mod;
            }
        }
    }
    pw2[0]=1;
    for (int i=1;i<=n;i++) pw2[i]=(pw2[i-1]*2)%mod;
    tot=n;

    string s;cin>>s;
    for (int i=0;i<s.size();i++){
        if (s[i]=='C') upd(i,1);
        else if (s[i]=='Z') upd(i,2);
    }
    cout<<solve()<<'\n';
    for (int i=1;i<=q;i++){
        int pos;cin>>pos;
        char c;cin>>c;
        pos--;
        if (c=='C') upd(pos,1);
        else if (c=='Z') upd(pos,2);
        else upd(pos,0);
        ll ans=solve();
        cout<<ans<<'\n';
    }

    return 0;
}