#include using namespace std; typedef long long ll; typedef long double ld; #define REP(i, n) for (int i = 0; i < (n); ++i) #define REPR(i, n) for (int i = n - 1; i >= 0; --i) #define FOR(i, m, n) for (int i = m; i < n; ++i) #define FORR(i, m, n) for (int i = m; i >= n; --i) #define ALL(v) (v).begin(),(v).end() #define ALLR(v) (v).rbegin(),(v).rend() #define fi first #define se second #define PB push_back #define EB emplace_back using P = pair; template using PQ = priority_queue; template using QP = priority_queue,greater>; templatevoid debug(const T &v,ll h,ll w){for(ll i=0;ivoid debug(const T &v,ll n){for(ll i=0;ivoid debug(const vector&v){debug(v,v.size());} templatevoid debug(const vector>&v){for(auto &vv:v)debug(vv,vv.size());} templatevoid debug(stack st){while(!st.empty()){cout<void debug(queue st){while(!st.empty()){cout<void debug(deque st){while(!st.empty()){cout<void debug(PQ st){while(!st.empty()){cout<void debug(QP st){while(!st.empty()){cout<void debug(const set&v){for(auto z:v)cout<void debug(const multiset&v){for(auto z:v)cout<void debug(const array &a){for(auto z:a)cout<void debug(const map&v){for(auto z:v)cout<<"["<bool chmax(T &a, const T &b) { if (abool chmin(T &a, const T &b) { if (b struct Matrix { vector< vector< T > > A; Matrix() {} Matrix(size_t n, size_t m) : A(n, vector< T >(m, 0)) {} Matrix(size_t n) : A(n, vector< T >(n, 0)) {}; size_t height() const { return (A.size()); } size_t width() const { return (A[0].size()); } inline const vector< T > &operator[](int k) const { return (A.at(k)); } inline vector< T > &operator[](int k) { return (A.at(k)); } static Matrix I(size_t n) { Matrix mat(n); for(int i = 0; i < n; i++) mat[i][i] = 1; return (mat); } Matrix &operator+=(const Matrix &B) { size_t n = height(), m = width(); assert(n == B.height() && m == B.width()); for(int i = 0; i < n; i++) for(int j = 0; j < m; j++) (*this)[i][j] += B[i][j]; return (*this); } Matrix &operator-=(const Matrix &B) { size_t n = height(), m = width(); assert(n == B.height() && m == B.width()); for(int i = 0; i < n; i++) for(int j = 0; j < m; j++) (*this)[i][j] -= B[i][j]; return (*this); } Matrix &operator*=(const Matrix &B) { size_t n = height(), m = B.width(), p = width(); assert(p == B.height()); vector< vector< T > > C(n, vector< T >(m, 0)); for(int i = 0; i < n; i++) for(int j = 0; j < m; j++) for(int k = 0; k < p; k++) C[i][j] = (C[i][j] + (*this)[i][k] * B[k][j]); A.swap(C); return (*this); } Matrix &operator^=(long long k) { Matrix B = Matrix::I(height()); while(k > 0) { if(k & 1) B *= *this; *this *= *this; k >>= 1LL; } A.swap(B.A); return (*this); } Matrix operator+(const Matrix &B) const { return (Matrix(*this) += B); } Matrix operator-(const Matrix &B) const { return (Matrix(*this) -= B); } Matrix operator*(const Matrix &B) const { return (Matrix(*this) *= B); } Matrix operator^(const long long k) const { return (Matrix(*this) ^= k); } T determinant() { Matrix B(*this); assert(width() == height()); T ret = 1; for(int i = 0; i < width(); i++) { int idx = -1; for(int j = i; j < width(); j++) { if(B[j][i] != 0) idx = j; } if(idx == -1) return (0); if(i != idx) { ret *= -1; swap(B[i], B[idx]); } ret *= B[i][i]; T vv = B[i][i]; for(int j = 0; j < width(); j++) { B[i][j] /= vv; } for(int j = i + 1; j < width(); j++) { T a = B[j][i]; for(int k = 0; k < width(); k++) { B[j][k] -= B[i][k] * a; } } } return (ret); } }; int main(){ cin.tie(0); ios::sync_with_stdio(false); int r,c,t;cin >> r >> c >> t; int sx,sy,gx,gy;cin >> sx >> sy >> gx >> gy; vector s(r); REP(i,r) cin >> s[i]; Matrix a(r*c),b(r*c,1); REP(i,r) REP(j,c){ if(s[i][j]=='#') continue; int cnt=0; REP(k,4){ int x=i+dx[k],y=j+dy[k]; if(s[x][y]!='#') cnt++; } if(cnt==0){ a[i*c+j][i*c+j]=1; continue; } REP(k,4){ int x=i+dx[k],y=j+dy[k]; if(s[x][y]!='#'){ a[x*c+y][i*c+j]=double(1)/cnt; } } } b[sx*c+sy][0]=1; Matrix res=(a^t)*b; cout << fixed << setprecision(10) << res[gx*c+gy][0] << endl; }