#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic warning "-Wunused-function"
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int h, w;
  cin >> h >> w;
  vector<string> s(h);
  VI v0, v1;
  rep(i, h) {
    cin >> s[i];
    rep(j, w) {
      if (s[i][j] == 'r') v0.emplace_back(i * w + j);
      else if (s[i][j] == 'h') v1.emplace_back(i * w + j);
    }
  }
  const int hw = h * w, b0 = hw + hw, b1 = b0 + v0.size(), src = b1 + v1.size(), snk = src + 1;
  mf_graph<int> g(snk + 1);
  rep(i, h - 1) rep(j, w) {
    int u = i * w + j, v = u + w;
    if (s[i][j] != 'h') g.add_edge(u, v, 1);
    if (s[i+1][j] != 'h') g.add_edge(v, u, 1);
  }
  rep(i, h) rep(j, w - 1) {
    int u = hw + i * w + j, v = u + 1;
    if (s[i][j] != 'h') g.add_edge(u, v, 1);
    if (s[i][j + 1] != 'h') g.add_edge(v, u, 1);
  }
  rep(i, v0.size()) {
    g.add_edge(src, b0 + i, 1);
    g.add_edge(b0 + i, v0[i], 1);
    g.add_edge(b0 + i, v0[i] + hw, 1);
  }
  rep(j, v1.size()) {
    g.add_edge(b1 + j, snk, 1);
    g.add_edge(v1[j], b1 + j, 1);
    g.add_edge(v1[j] + hw, b1 + j, 1);
  }
  int f = g.flow(src, snk);
  cout << (f == v0.size() ? "Yes\n" : "No\n");
}