#include <bits/stdc++.h>
using namespace std;
#define all(c) (c).begin(),(c).end()
#define rrep(i,n) for(int i=(int)(n)-1;i>=0;i--)
#define REP(i,m,n) for(int i=(int)(m);i<(int)(n);i++)
#define rep(i,n) REP(i,0,n)
#define iter(c) __typeof((c).begin())
#define tr(it,c) for(iter(c) it=(c).begin();it!=(c).end();it++)
#define pb(a) push_back(a)
#define pr(a) cout<<(a)<<endl
#define PR(a,b) cout<<(a)<<" "<<(b)<<endl
#define R cin>>
#define F first
#define S second
#define ll long long
bool check(int n,int m,int x,int y){return x>=0&&x<n&&y>=0&&y<m;}
const ll MAX=1000000007,MAXL=1LL<<60,dx[4]={-1,0,1,0},dy[4]={0,1,0,-1};
typedef pair<int,int> P;

int main() {
  int n,m,k;
  cin >> m >> n >> k;
  string r[m],t[n];
  rep(i,m) R r[i];
  rep(i,n) {
    rep(j,m) t[i]+=r[m-j-1][i];
  }
  bool ck=false;
  rep(i,n-1) {
    rep(j,m) {
      if(!check(n,m,i+1,j) || (t[i][j]=='.' && t[i+1][j]=='.')) continue;
      string s[n];
      rep(x,n) s[x]=t[x];
      swap(s[i][j],s[i+1][j]);
      rep(x,n) fill(remove(s[x].begin(),s[x].end(),'.'),s[x].end(),'.');
      while(1) {
	bool e[n][m],f=false;
	memset(e,0,sizeof(e));
	rep(x,n) {
	  rep(y,m) {
	    if(s[x][y]=='.') continue;
	    REP(l,1,3) {
	      int cnt=0;
	      int c=(l==1?m:n);
	      rep(p,c+1) {
		int nx=x+dx[l]*p,ny=y+dy[l]*p;
		if(!check(n,m,nx,ny) || s[nx][ny]!=s[x][y]) break;
		cnt++;
	      }
	      if(cnt>=k) {
		f=true;
		rep(p,c+1) {
		  int nx=x+dx[l]*p,ny=y+dy[l]*p;
		  if(!check(n,m,nx,ny) || s[nx][ny]!=s[x][y]) break;
		  e[nx][ny]=1;
		}
	      }
	    }
	  }
	}
	rep(x,n) rep(y,m) if(e[x][y]) s[x][y]='.';
	rep(x,n) fill(remove(s[x].begin(),s[x].end(),'.'),s[x].end(),'.');
	int c=0;
	rep(x,n) rep(y,m) if(s[x][y]!='.') c++;
	if(!c) {
	  ck=true;
	  break;
	}
	if(!f) break;
      }
      if(ck) break;
    }
    if(ck) break;
  }
  if(ck) pr("YES");
  else pr("NO");
  return 0;
}
