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// Tak, wiem, że da się w O(1) na zapytanie, ciii.
#include <bits/stdc++.h>

#define ALL(x) (x).begin(), (x).end()
#define SZ(x) ((int)(x).size())
#define st first
#define nd second

using namespace std;
 
#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 LOCAL
~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__) << "] "
 
using ll = long long;
using pii = pair<int,int>;
using pll = pair<ll,ll>;
using vi = vector<int>;
using vll = vector<ll>;

const int mod = 1000 * 1000 * 1000 + 7;

struct SegTree {
	struct Node {
		int num_ways[3];
		Node() {
			memset(num_ways, 0, sizeof(num_ways));
		}
		Node Merge(const Node &rhs) const {
			Node ans;
			for (int i = 0; i < 3; ++i) {
				ll x = 0;
				for (int j = 0; j < 3; ++j) {
					x += (ll)num_ways[j] * rhs.num_ways[(i - j + 3) % 3];
				}
				ans.num_ways[i] = x % mod;
			}
			return ans;
		}
	};
	
	vector<Node> nodes;
	int base;
	
	SegTree(int n) : base(1) {
		while (base < n + 2) { base *= 2; }
		nodes.resize(base * 2);
		for (int i = 1; i < base * 2; ++i) {
			nodes[i].num_ways[0] = 1;
		}
	}
	
	void PutVal(int where, int n1, int n2) {
		where += base;
		nodes[where].num_ways[0] = 0;
		nodes[where].num_ways[1] = n1;
		nodes[where].num_ways[2] = n2;
		where /= 2;
		while (where) {
			nodes[where] = nodes[where * 2].Merge(nodes[where * 2 + 1]);
			where /= 2;
		}
	}
	
	int GetNumOK() const {
		return (nodes[1].num_ways[1] + nodes[1].num_ways[2]) % mod;
	}
};



int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout << fixed << setprecision(11);
	cerr << fixed << setprecision(6);

	string cur_str;
	int n, q;
	cin >> n >> q >> cur_str;
	SegTree st(n + 1);
	
	int fails_cz = 0, fails_zc = 0;
	
	auto AddChar = [&](int loc, char ch) {
		cur_str[loc] = ch;
		st.PutVal(loc, ch != 'C', ch != 'Z');
		
		if (ch == 'C') {
			++(loc % 2 == 0 ? fails_zc : fails_cz);
		} else if (ch == 'Z') {
			++(loc % 2 == 0 ? fails_cz : fails_zc);
		}
	};
	
	auto DelChar = [&](int loc, char ch) {
		if (ch == 'C') {
			--(loc % 2 == 0 ? fails_zc : fails_cz);
		} else if (ch == 'Z') {
			--(loc % 2 == 0 ? fails_cz : fails_zc);
		}
	};
	
	auto GetResult = [&]() {
		int ans = st.GetNumOK();
		if (n >= 3 && n % 2 == 1 && fails_cz == 0) { --ans; }
		if (n >= 3 && n % 2 == 1 && fails_zc == 0) { --ans; }
		return (ans + mod) % mod;
	};
	
	for (int i = 0; i < n; ++i) {
		AddChar(i, cur_str[i]);
	}
	
	cout << GetResult() << "\n";
	for (int i = 0; i < q; ++i) {
		int loc;
		char ch;
		cin >> loc >> ch;
		--loc;
		DelChar(loc, cur_str[loc]);
		AddChar(loc, ch);
		cout << GetResult() << "\n";
	}
}