#include <cmath>
#include <cstdint>
#include <complex>
#include <iostream>
#include <vector>
#define FOR(i,k,n)  for(int i = (k);i < (n);++i)
#define REP(i,n)    FOR(i,0,n)
#define ALL(x)      begin(x),end(x)

using namespace std;
using vecint = vector<int>;
using ll = int64_t;
using vecll = vector<ll>;

using P = complex<double>;

const double pi = acos(-1.0);

vector<P> FFT(double theta, const vector<P> &a) {
  const int n = a.size();
  vector<P> ret = a;
  for (int m = n; m >= 2; m >>= 1, theta *= 2) {
    REP(i,m/2) {
      for (int j = i; j < n; j += m) {
        int k = j + m / 2;
        P x = ret[j] - ret[k];
        ret[j] += ret[k];
        ret[k] = exp(i * theta * P(0, 1)) * x;
      }
    }
  }
  for (int i = 0, j = 1; j < n - 1; j++) {
    for (int k = n >> 1; k > (i ^= k); k >>= 1) {;}
    if (j < i) swap(ret[i], ret[j]);
  }
  return ret;
}

vector<ll> convolution(const vector<ll> &lhs, const vector<ll> &rhs) {
  int n = 1, a = lhs.size(), b = rhs.size();
  while (n < max(a, b) * 2) n <<= 1;
  vector<P> temp1(n), temp2(n);
  REP(i,n/2) {
    if (i < a) temp1[i] = P(lhs[i], 0);
    if (i < b) temp2[i] = P(rhs[i], 0);
  }
  temp1 = FFT(2.0 * pi / n, temp1);
  temp2 = FFT(2.0 * pi / n, temp2);
  REP(i,n) temp1[i] *= temp2[i];
  temp1 = FFT(-2.0 * pi / n, temp1);
  vector<ll> ret(n);
  REP(i,n) ret[i] = temp1[i].real() / n + 0.5;
  return ret;
}

constexpr ll MOD = 998244353;
constexpr ll MAX_F = 600000;

// a^-1 mod p
ll inv(ll a,ll p){
  return ( a == 1 ? 1 : (1 - p*inv(p%a,a)) / a + p );
}

int main() {
  vecll fact(MAX_F+1), finv(MAX_F+1);
  fact[0] = 1;
  REP(i,MAX_F) {
    fact[i+1] = fact[i] * (i+1) % MOD;
  }
  finv[MAX_F] = inv(fact[MAX_F], MOD);
  REP(ri,MAX_F) {
    int i = MAX_F - ri;
    finv[i-1] = finv[i] * i % MOD;
  }
  auto comb = [&] (ll n, ll k) {
    return fact[n] * finv[k] % MOD * finv[n-k] % MOD;
  };
  ll n,k;
  cin>>n>>k;
  string s;
  cin>>s;
  vecll left_i(n, 0), right_n(n, 0);
  REP(i,n) {
    if (s[i] == 'i') {
      left_i[i] = 1;
    } else {
      right_n[n-1-i] = 1;
    }
  }
  auto poly = convolution(left_i, right_n);
  ll ans = 0;
  REP(i,n-k-1) {
    ll span = n-2-i;
    ans += poly[i] * comb(span,k) % MOD;
    ans %= MOD;
  }
  cout<<ans<<"\n";
  return 0;
}