void main(){
  import std.stdio, std.string, std.conv, std.algorithm;

  int h, w, t; rd(h, w, t);
  int sy, sx; rd(sy, sx);
  int gy, gx; rd(gy, gx);
  auto c=new char[][](h, w);
  foreach(i; 0..h) c[i]=readln.chomp.to!(char[]);

  const double eps=1e-9;
  const int[][] dir=[[1, 0], [-1, 0], [0, 1], [0, -1]];
  
  auto dp=new double[][](h, w);
  foreach(i; 0..h) fill(dp[i], 0.0);
  dp[sy][sx]=1.0;
  foreach(_; 0..min(t, 1_000_00+t%2)){
    auto nex=new double[][](h, w);
    foreach(i; 0..h) fill(nex[i], 0.0);    
    foreach(i; 0..h)foreach(j; 0..w){
      if(c[i][j]=='#') continue;
      if(dp[i][j]<eps) continue;
      int sum=0;
      foreach(d; dir){
        auto ni=i+d[0], nj=j+d[1];
        if((0<ni && ni<h && 0<nj && nj<w)==false) continue;
        if(c[ni][nj]=='#') continue;
        sum++;
      }
      if(sum==0){nex[i][j]=dp[i][j]; continue;}
      foreach(d; dir){
        auto ni=i+d[0], nj=j+d[1];
        if((0<ni && ni<h && 0<nj && nj<w)==false) continue;
        if(c[ni][nj]=='#') continue;        
        nex[ni][nj]+=dp[i][j]/sum;
      }
    }
    dp.swap(nex);
  }
  writefln("%.18f", dp[gy][gx]);
}

void rd(T...)(ref T x){
  import std.stdio, std.string, std.conv;
  auto l=readln.split;
  assert(l.length==x.length);
  foreach(i, ref e; x){
    e=l[i].to!(typeof(e));
  }
}