#include <cstdlib>
#include <cmath>
#include <climits>
#include <cfloat>
#include <map>
#include <set>
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>
#include <cstdio>
#include <cstring>
#include <iterator>
#include <bitset>
#include <unordered_set>
#include <unordered_map>
#include <fstream>
#include <iomanip>
//#include <utility>
//#include <memory>
//#include <functional>
//#include <deque>
//#include <cctype>
//#include <ctime>
//#include <numeric>
//#include <list>
//#include <iomanip>

//#if __cplusplus >= 201103L
//#include <array>
//#include <tuple>
//#include <initializer_list>
//#include <forward_list>
//
//#define cauto const auto&
//#else

//#endif

using namespace std;


typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

typedef vector<int> vint;
typedef vector<vector<int> > vvint;
typedef vector<long long> vll, vLL;
typedef vector<vector<long long> > vvll, vvLL;

#define VV(T) vector<vector< T > >

template <class T>
void initvv(vector<vector<T> > &v, int a, int b, const T &t = T()){
    v.assign(a, vector<T>(b, t));
}

template <class F, class T>
void convert(const F &f, T &t){
    stringstream ss;
    ss << f;
    ss >> t;
}

#undef _P
#define _P(...) (void)printf(__VA_ARGS__)
#define reep(i,a,b) for(int i=(a);i<(b);++i)
#define rep(i,n) reep((i),0,(n))
#define ALL(v) (v).begin(),(v).end()
#define PB push_back
#define F first
#define S second
#define mkp make_pair
#define RALL(v) (v).rbegin(),(v).rend()
#define DEBUG
#ifdef DEBUG
#define dump(x)  cout << #x << " = " << (x) << endl;
#define debug(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;
#else
#define dump(x) 
#define debug(x) 
#endif
#define LDcout(x,n) fixed<<setprecision(n)<<x

#define MOD 1000000007LL
#define EPS 1e-8
static const int INF=1<<24;

int h,w;
int n;
bool check(vector<string> &v){
	rep(i,h){
		rep(j,w){
			if(v[i][j]!='.') return false;
		}
	}
	return true;
}
bool foo(vector<string> v){
	vvint vv;
	// cout<<"aa"<<endl;
	// rep(i,h) cout<<v[i]<<endl;
	// cout<<endl;
	bool update=true;
	while(update){
		update=false;
		initvv(vv,h,w,0);
		for(int i=h-1;i>=0;i--){
			rep(j,w){
				if(v[i][j]!='.'){
					char t=v[i][j];
					v[i][j]='.';
					int pos=i;
					while(pos+1<h&&v[pos+1][j]=='.'){
						pos++;
					}
					v[pos][j]=t;
				}
			}
		}
		rep(i,h-n+1){
			rep(j,w){
				bool tt=true;
				if(v[i][j]=='.') continue;
				reep(k,i,i+n-1){
					if(v[k][j]!=v[k+1][j]) tt=false;
				}
				if(tt){
					update=true;
					reep(k,i,i+n){
						vv[k][j]=1;
					}
				}
			}
		}
		rep(i,h){
			rep(j,w-n+1){
				bool tt=true;
				if(v[i][j]=='.') continue;
				reep(k,j,j+n-1){
					if(v[i][k]!=v[i][k+1]) tt=false;
				}
				if(tt){
					update=true;
					reep(k,j,j+n){
						vv[i][k]=1;
					}
				}
			}
		}
		if(!update) break;
		rep(i,h){
			rep(j,w){
				if(vv[i][j]==1){
					v[i][j]='.';
				}
			}
		}
		// rep(i,h) cout<<v[i]<<endl;
		// cout<<endl;
		// rep(i,h) cout<<v[i]<<endl;
		if(check(v)){
			// cout<<0<<endl;
			return true;
		}
	}
	return false;
}

void mainmain(){
	cin>>h>>w>>n;
	vector<string> v(h);
	rep(i,h) cin>>v[i];
	bool f=false;
	rep(i,h){
		rep(j,w-1){
			swap(v[i][j],v[i][j+1]);
			f|=foo(v);
			swap(v[i][j],v[i][j+1]);
		}
	}
	// f=foo(v);
	if(f){
		puts("YES");
	}
	else{
		puts("NO");
	}
}


signed main() {
	ios_base::sync_with_stdio(false);
  	cout<<fixed<<setprecision(0);
    mainmain();
}

Measured memory_bytes: 1228