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#include <algorithm>
#include <cstdint>
#include <ios>
#include <iostream>
#include <iterator>
#include <limits>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <vector>

template <typename T> void print_value(const T &v);

template <typename T> void debug(const T &v, const std::string &s) {
  std::cerr << s << ": '";
  print_value(v);
  std::cerr << "'\n";
}

template <> void print_value(const std::vector<int32_t> &v) {
  for (const auto x : v) {
    std::cerr << x << " ";
  }
}
template <> void print_value(const std::unordered_set<int32_t> &v) {
  for (const auto x : v) {
    std::cerr << x << " ";
  }
}

template <typename T> void print_value(const T &v) { std::cerr << v; }

void prelude() {
  std::ios_base::sync_with_stdio(false);
  std::cin.tie(NULL);
}
bool viable(int k, int n) {
  int red = k;
  int green = n - k;
  while (red > 1 || green > 1) {
    if (green > red) {
      using std::swap;
      swap(green, red);
    }
    // red >= green
    green += red / 2;
    red -= (red / 2) * 2;
  }
  return red == 0 || green == 0;
}

class Bin {
public:
  Bin(std::vector<int64_t> rep) : rep_(std::move(rep)) {}
  int64_t get(int index, int mod) const { return rep_[3 * index + mod]; }

private:
  std::vector<int64_t> rep_;
};

constexpr int64_t kMod = 1'000'000'007;

Bin binomial_mod_3(int n) {
  std::vector<int64_t> result;
  result.reserve(3 * n + 3);
  result.push_back(1);
  result.push_back(0);
  result.push_back(0);
  for (int i = 0; i < n; ++i) {
    result.push_back((result[3 * i] + result[3 * i + 2]) % kMod);
    result.push_back((result[3 * i + 1] + result[3 * i]) % kMod);
    result.push_back((result[3 * i + 2] + result[3 * i + 1]) % kMod);
  }
  return Bin(result);
};

bool violates_zcz(char c, int idx) {
  return (c == 'Z' && idx % 2 == 1) || (c == 'C' && idx % 2 == 0);
}

bool violates_czc(char c, int idx) {
  return (c == 'C' && idx % 2 == 1) || (c == 'Z' && idx % 2 == 0);
}
int64_t count(const Bin &bin, const std::unordered_set<int> &violations_czc,
              const std::unordered_set<int> &violations_zcz,
              const std::unordered_map<char, int> &counts, int n) {
  //debug(violations_zcz, "zcz");
  //debug(violations_czc, "czc");
  int excluded_mod = (3 - (n % 3)) % 3;
  int starts_at_mod = counts.at('Z') % 3;
  int excluded_adjusted_mod = (3 + excluded_mod - starts_at_mod) % 3;
  int n_count = counts.at('N');
  int64_t result =
      (kMod +
       (bin.get(n_count, 0) + bin.get(n_count, 1) + bin.get(n_count, 2)) %
           kMod -
       bin.get(n_count, excluded_adjusted_mod)) %
      kMod;
  // Edge cases
  bool violations_counted = n % 2 == 1 && n > 1;
  int64_t violations_to_subtract = violations_counted
                                       ? ((violations_czc.empty() ? 1 : 0) +
                                          (violations_zcz.empty() ? 1 : 0))
                                       : 0;
  //debug(violations_counted, "violations_counted");                            
  result = (kMod + result - violations_to_subtract) % kMod;
  return result;
}

int main() {
  prelude();
  int n;
  int q;
  std::string str;
  std::cin >> n >> q;
  std::cin.ignore();
  std::getline(std::cin, str);

  std::unordered_map<char, int> counts;
  counts['Z'] = counts['N'] = counts['C'] = 0;
  std::unordered_set<int> violations_czc;
  std::unordered_set<int> violations_zcz;
  for (int i = 0; i < str.length(); ++i) {
    counts[str[i]]++;
    if (violates_czc(str[i], i))
      violations_czc.insert(i);
    if (violates_zcz(str[i], i))
      violations_zcz.insert(i);
  }
  const auto bin = binomial_mod_3(n);
  std::cout << count(bin,violations_czc, violations_zcz, counts, n) << "\n";
  while (q--) {
    int idx;
    char c;
    std::cin >> idx >> c;
    // Input 1-based.
    idx -= 1;
    //debug(idx, "idx");
    //debug(c, "c");
    char previous_c = str[idx];
    str[idx] = c;
    counts[previous_c]--;
    counts[c]++;
    violations_czc.erase(idx);
    violations_zcz.erase(idx);

    if (violates_czc(c, idx))
      violations_czc.insert(idx);
    if (violates_zcz(c, idx))
      violations_zcz.insert(idx);
    std::cout << count(bin, violations_czc, violations_zcz, counts, n) << "\n";
  }
  // On each iteration:
  // - update CZN, corner case sets and position
  // - determine mod3 of C/Z vs equal mod3 to calculate
  // - subtract for corner cases
  return 0;
}