#include <bits/stdc++.h>
using namespace std;
#define SZ(x) (int)(x.size())
#define REP(i, n) for(int i=0;i<(n);++i)
#define FOR(i, a, b) for(int i=(a);i<(b);++i)
#define RREP(i, n) for(int i=(int)(n)-1;i>=0;--i)
#define RFOR(i, a, b) for(int i=(int)(b)-1;i>=(a);--i)
#define ALL(a) a.begin(),a.end()
#define DUMP(x) cerr<<#x<<" = "<<(x)<<endl
#define DEBUG(x) cerr<<#x<<" = "<<(x)<<" (L"<<__LINE__<<")"<< endl;
using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using P = pair<int, int>;
const double eps = 1e-8;
const ll MOD = 1000000007;
const int INF = INT_MAX / 2;
const ll LINF = LLONG_MAX / 2;
template <typename T1, typename T2>
bool chmax(T1 &a, const T2 &b) {
    if (a < b) { a = b; return true; }
    return false;
}
template <typename T1, typename T2>
bool chmin(T1 &a, const T2 &b) {
    if (a > b) { a = b; return true; }
    return false;
}
template<typename T>
ostream &operator<<(ostream &os, const vector<T> &v) {
    os << "[";
    REP(i, SZ(v)) {
        if (i) os << ", ";
        os << v[i];
    }
    return os << "]";
}
template<typename T1, typename T2>
ostream &operator<<(ostream &os, const map<T1, T2> &mp) {
    os << "{";
    int a = 0;
    for (auto &tp : mp) {
        if (a) os << ", "; a = 1;
        os << tp;
    }
    return os << "}";
}
template<typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
    os << p.first << ":" << p.second;
    return os;
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);

    int H, W, N; cin >> H >> W >> N;
    vector<string> board(H);
    REP(i, H) cin >> board[i];

    const int dy[] = {0, 1, 0, -1};
    const int dx[] = {1, 0, -1, 0};

    auto check = [&](vector<string> board) {
        bool updated = true;
        while (updated) {
            updated = false;

            REP(_, H) {
                REP(i, H - 1) {
                    REP(j, W) {
                        if (board[i][j] != '.' and board[i + 1][j] == '.') {
                            swap(board[i][j], board[i + 1][j]);
                        }
                    }
                }
            }

            vvi remove(H, vi(W));
            REP(c, 26) {
                REP(i, H) {
                    REP(j, W) {
                        REP(k, 4) {
                            int cnt = 0;
                            int y = i, x = j;
                            while (0 <= y and y < H and 0 <= x and x < W and board[y][x] == c + 'A') {
                                y += dy[k], x += dx[k], ++cnt;
                            }
                            if (cnt < N) continue;
                            y = i, x = j;
                            while (0 <= y and y < H and 0 <= x and x < W and board[y][x] == c + 'A') {
                                remove[y][x] = 1;
                                y += dy[k], x += dx[k];
                            }
                        }
                    }
                }
            }

            REP(i, H) REP(j, W) {
                if (remove[i][j]) {
                    updated = 1;
                    board[i][j] = '.';
                }
            }

            REP(_, H) {
                REP(i, H - 1) {
                    REP(j, W) {
                        if (board[i][j] != '.' and board[i + 1][j] == '.') {
                            swap(board[i][j], board[i + 1][j]);
                        }
                    }
                }
            }
        }

        int ret = 1;
        REP(i, H) REP(j, W) if (board[i][j] != '.') ret = 0;
        return ret;
    };

    int ans = 0;
    REP(i, H) REP(j, W-1) {
        swap(board[i][j], board[i][j+1]);
        ans |= check(board);
        swap(board[i][j], board[i][j+1]);
    }

    cout << (ans ? "YES" : "NO") << endl;

    return 0;

}



Measured memory_bytes: 3248