1008

  1 #include <bits/stdc++.h>
  2 
  3 using namespace std;
  4 
  5 #define REP(i,n)                for(int i(0); i <  (n); ++i)
  6 #define rep(i,a,b)              for(int i(a); i <= (b); ++i)
  7 #define dec(i,a,b)              for(int i(a); i >= (b); --i)
  8 #define for_edge(i,x)           for(int i = H[x]; i; i = X[i])
  9 
 10 #define LL      long long
 11 #define ULL     unsigned long long
 12 #define MP      make_pair
 13 #define PB      push_back
 14 #define FI      first
 15 #define SE      second
 16 #define INF     1 << 30
 17 
 18 const int N     =    100000      +       10;
 19 const int M     =    10000       +       10;
 20 const int Q     =    1000        +       10;
 21 const int A     =    100          +       1;
 22 
 23 const int dx[] = {0, 1, 0, -1};
 24 const int dy[] = {1, 0, -1, 0};
 25 
 26 const int cx[] = {2, 0, -2, 0, 1, -1, 1, -1};
 27 const int cy[] = {0, 2, 0, -2, 1, -1, -1, 1};
 28 
 29 struct node{
 30     int x, y, k, t;
 31 } st, en;
 32 
 33 char s[Q];
 34 int n, m, k, t;
 35 int a[A][A];
 36 queue <node> q;
 37 int f[A][A];
 38 
 39 
 40 bool check(int x, int y){
 41     return (x >= 1)  && (x <= m) && (y >= 1) && (y <= n);
 42 }
 43 
 44 int main(){
 45 #ifndef ONLINE_JUDGE
 46     freopen("test.txt", "r", stdin);
 47     freopen("test.out", "w", stdout);
 48 #endif
 49 
 50     while (~scanf("%d%d%d%d", &m, &n, &k, &t), n + m + k + t){
 51         memset(a, 0, sizeof a);
 52         rep(i, 1, m){
 53             scanf("%s", s + 1);
 54             rep(j, 1, n){
 55                 if (s[j] == ‘#‘){
 56                     a[i][j] = 1;
 57                 }
 58                 else{
 59                     a[i][j] = 0;
 60                     if (s[j] == ‘@‘) st.x = i, st.y = j;
 61                     if (s[j] == ‘X‘) en.x = i, en.y = j;
 62                 }
 63             }
 64 
 65         }
 66         while (!q.empty()) q.pop();
 67         st.k = k;
 68         st.t = t;
 69         q.push(st);
 70         memset(f, -1, sizeof f);
 71         f[st.x][st.y] = k;
 72         int ans = 0;
 73         while (!q.empty()){
 74             node now = q.front(); q.pop();
 75             if (now.x == en.x && now.y == en.y && now.t >= 0){
 76                 ans = 1;
 77                 break;
 78             }
 79             REP(i, 4){
 80                 node nn;
 81                 nn.x = now.x + dx[i];
 82                 nn.y = now.y + dy[i];
 83                 if (check(nn.x, nn.y) && f[nn.x][nn.y] < now.k && !a[nn.x][nn.y]){
 84                     nn.k = now.k;
 85                     nn.t = now.t - 1;
 86                     if (nn.t >= 0){
 87                         q.push(nn);
 88                         f[nn.x][nn.y] = nn.k;
 89                     }
 90                 }
 91             }
 92             if (now.k > 0){
 93                 REP(i, 8){
 94                     node nn;
 95                     nn.x = now.x + cx[i];
 96                     nn.y = now.y + cy[i];
 97                     if (check(nn.x, nn.y) && f[nn.x][nn.y] < now.k - 1 && !a[nn.x][nn.y]){
 98                         nn.k = now.k - 1;
 99                         nn.t = now.t - 1;
100                         if (nn.t >= 0){
101                             q.push(nn);
102                             f[nn.x][nn.y] = nn.k;
103                         }
104                     }
105                 }
106             }
107         }
108         if (ans) puts("Yes"); else puts("No");
109     }
110     return 0;
111 
112 }