/* -*- coding: utf-8 -*-
 *
 * 659.cc: No.659 徘徊迷路 - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_H = 10;
const int MAX_W = 10;
const int MAX_N = (MAX_H - 2) * (MAX_W - 2);

const int dxs[] = { 1, 0, -1, 0 }, dys[] = { 0, -1, 0, 1 };

/* typedef */

typedef double vec[MAX_N];
typedef vec mat[MAX_N];

/* global variables */

string flds[MAX_H];

/* subroutines */

inline void initvec(int n, vec a) { fill(a, a + n, 0.0); }
inline void initmat(int n, mat a) {
  for (int i = 0; i < n; i++) initvec(n, a[i]);
}

inline void unitmat(int n, mat a) {
  initmat(n, a);
  for (int i = 0; i < n; i++) a[i][i] = 1.0;
}

inline void copymat(int n, const mat a, mat b) { memcpy(b, a, sizeof(mat)); }

inline void addmat(int n, const mat a, const mat b, mat c) {
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++) c[i][j] = a[i][j] + b[i][j];
}

inline void mulmat(int n, const mat a, const mat b, mat c) {
  for (int i = 0; i < n; i++)
    for (int j = 0; j < n; j++) {
      c[i][j] = 0.0;
      for (int k = 0; k < n; k++)
        c[i][j] += a[i][k] * b[k][j];
    }
}

inline void powmat(int n, const mat a, int b, mat c) {
  mat s, t;
  copymat(n, a, s);
  unitmat(n, c);

  while (b > 0) {
    if (b & 1) {
      mulmat(n, c, s, t);
      copymat(n, t, c);
    }

    mulmat(n, s, s, t);
    copymat(n, t, s);
    b >>= 1;
  }
}

inline void mulmatvec(int n, const mat a, const vec b, vec c) {
  for (int i = 0; i < n; i++) {
    c[i] = 0.0;
    for (int j = 0; j < n; j++) c[i] += a[i][j] * b[j];
  }
}

inline int xy2p(int x, int y, int w) { return (y - 1) * (w - 2) + (x - 1); }

/* main */

int main() {
  int h, w, t;
  cin >> h >> w >> t;

  int sy, sx, gy, gx;
  cin >> sy >> sx >> gy >> gx;

  for (int y = 0; y < h; y++) cin >> flds[y];

  int n = (h - 2) * (w - 2);
  mat a;
  initmat(n, a);

  for (int y = 1; y < h - 1; y++)
    for (int x = 1; x < w - 1; x++)
      if (flds[y][x] == '.') {
	int cnt = 0, p = xy2p(x, y, w);
	bool bs[4] = { false };
	for (int di = 0; di < 4; di++) {
	  int vx = x + dxs[di], vy = y + dys[di];
	  if (flds[vy][vx] == '.') cnt++, bs[di] = true;
	}

	if (cnt == 0) a[p][p] = 1.0;
	else
	  for (int di = 0; di < 4; di++)
	    if (bs[di]) {
	      int vx = x + dxs[di], vy = y + dys[di], vp = xy2p(vx, vy, w);
	      a[p][vp] = 1.0 / cnt;
	    }
      }

  mat c;
  powmat(n, a, t, c);

  int sp = xy2p(sx, sy, w), gp = xy2p(gx, gy, w);

  printf("%.16lf\n", c[sp][gp]);
  return 0;
}