#include <iostream>
#include <cstdio>
#include <vector>
#include <list>
#include <cmath>
#include <fstream>
#include <algorithm>
#include <string>
#include <queue>
#include <set>
#include <map>
#include <complex>
#include <iterator>
#include <cstdlib>
#include <cstring>
#include <sstream>
#include <stack>
#include <climits>
#include <deque>
#include <bitset>
#include <cassert>
#include <ctime>

using namespace std;

typedef long long ll;
typedef pair<int,int> pii;
// adjust problem by problem
const double EPS=1e-8;
const double PI=acos(-1.0);
#ifdef __GNUC__
int popcount(int n){return __builtin_popcount(n);}
int popcount(ll n){return __builtin_popcountll(n);}
#endif
#ifndef __GNUC__
template<class T> int popcount(T n){int cnt=0;while(n){if(n%2)cnt++;n/=2;}return cnt;}
#endif
template<class T>int SIZE(T a){return a.size();}
template<class T>string IntToString(T num){string res;stringstream ss;ss<<num;return ss.str();}
template<class T>T StringToInt(string str){T res=0;for(int i=0;i<SIZE(str);i++)res=(res*10+str[i]-'0');return res;}
template<class T>T gcd(T a,T b){if(b==0)return a;return gcd(b,a%b);}
template<class T>T lcm(T a,T b){return a/gcd(a,b)*b;}
template<class T> void PrintSeq(T &a,int sz){for(int i=0;i<sz;i++){cout<<a[i];if(sz==i+1)cout<<endl;else cout<<' ';}}
bool EQ(double a,double b){return abs(a-b)<EPS;}
void fastStream(){cin.tie(0);std::ios_base::sync_with_stdio(0);}
vector<string> split(string str,char del){
  vector<string> res;
  for(int i=0,s=0;i<SIZE(str);i++){
    if(str[i]==del){if(i-s!=0)res.push_back(str.substr(s,i-s));s=i+1;}
    else if(i==SIZE(str)-1){res.push_back(str.substr(s));}
  }
  return res;
}

int H,W,K;
char field[51][51];
int dp[51][51][1<<10][4][4];
bool used[51][51][1<<10][4][4];

const int dy[]={-1,0,1,0},dx[]={0,1,0,-1};
pii getNxtMaskAndVal(int cy,int cx,int mask,int my,int mx,int ang){
  int nmask=mask;
  int oy=cy+my;
  int ox=cx+mx;
  int cnt=0;
  int val=0;
  map<pii,int> m;
  for(int i=-3;i<=0;i++)
    for(int j=0;abs(i)+abs(j)<=3;j--)
      m[pii(i+oy,j+ox)]=cnt,cnt++;
  if(ang==0||ang==3){
    int ny=cy+dy[ang];
    int nx=cx+dx[ang];
    int nidx=m[pii(ny,nx)];
    if(ny>=0&&nx>=0&&ny<H&&nx<W&&field[ny][nx]!='#'){
      if(field[ny][nx]!='.'&&!((nmask>>nidx)&1))
        val+=field[ny][nx]-'0';
    }
    nmask|=(1<<nidx);
  }
  // テ・ツ?ィテ、ツスツ禿」ツ?ョテ」ツδ禿」ツδε」ツδ暗・ツ渉ウテ」ツ?ォテ」ツつ津」ツつキテ」ツδ陛」ツδ?
  else if(ang==1){
    int ny=cy+dy[ang];
    int nx=cx+dx[ang];
    nmask=0;
    nmask|=(((mask>>1)&1)<<2);
    nmask|=(((mask>>3)&1)<<4);
    nmask|=(((mask>>4)&1)<<5);
    nmask|=(((mask>>6)&1)<<7);
    nmask|=(((mask>>7)&1)<<8);
    nmask|=(((mask>>8)&1)<<9);
    int nidx=m[pii(cy,cx)];
    if(ny>=0&&nx>=0&&ny<H&&nx<W&&field[ny][nx]!='#'){
      if(field[ny][nx]!='.'&&!((nmask>>nidx)&1))
        val+=field[ny][nx]-'0';
    }
    nmask|=(1<<nidx);
  }
  // テ、ツクツ凝ヲツ鳴ケテ・ツ青妥」ツ?ォテ」ツδ禿」ツδε」ツδ暗」ツつ津」ツつキテ」ツδ陛」ツδ?
  else if(ang==2){
    int ny=cy+dy[ang];
    int nx=cx+dx[ang];
    nmask=0;
    nmask|=(((mask>>1)&1)<<0);
    nmask|=(((mask>>3)&1)<<1);
    nmask|=(((mask>>4)&1)<<2);
    nmask|=(((mask>>6)&1)<<3);
    nmask|=(((mask>>7)&1)<<4);
    nmask|=(((mask>>8)&1)<<5);
    int nidx=m[pii(cy,cx)];
    if(ny>=0&&nx>=0&&ny<H&&nx<W&&field[ny][nx]!='#')
      if(field[ny][nx]!='.'&&!((nmask>>nidx)&1))
        val+=field[ny][nx]-'0';
    nmask|=(1<<nidx);
  }
  return pii(nmask,val);
}

struct Sit{
  int cy,cx,mask,my,mx;
  Sit(){}
  Sit(int cy_,int cx_,int mask_,int my_,int mx_){
    cy=cy_;
    cx=cx_;
    mask=mask_;
    my=my_;
    mx=mx_;
  }
  bool operator<(const Sit&sit)const{
    return true;
  }
};
typedef pair<int,Sit> iSit;

const int INF=(1<<30);
int dfs(int cy,int cx,int mask,int my,int mx){
  if(used[cy][cx][mask][my][mx])return dp[cy][cx][mask][my][mx];
  int res=-INF;
  int leftK=K-(my+mx);
  for(int i=0;i<4;i++){
    int ny=cy+dy[i];
    int nx=cx+dx[i];
    if(ny>=0&&nx>=0&&ny<H&&nx<W&&field[ny][nx]!='#'){
      pii p=getNxtMaskAndVal(cy,cx,mask,my,mx,i);
      int nmask=p.first;
      int nAddVal=p.second;
      // cout<<nAddVal<<endl;
      if(leftK>0&&(i==0||i==3)){
        res=max(res,dfs(ny,nx,nmask,my+abs(dy[i]),mx+abs(dx[i]))+nAddVal);
      }
      else if((i==1||i==2)){
        res=max(res,dfs(ny,nx,nmask,my,mx)+nAddVal);
      }
    }
  }
  if(cy==H-1&&cx==W-1)res=max(res,0);
  used[cy][cx][mask][my][mx]=true;
  return dp[cy][cx][mask][my][mx]=res;
}

int dijkstra(){
  memset(dp,-1,sizeof(dp));
  dp[0][0][1<<6][0][0]=0;
  priority_queue<iSit> pq;
  pq.push(make_pair(0,Sit(0,0,1<<6,0,0)));
  while(pq.size()){
    iSit is=pq.top();pq.pop();
    int cval=is.first;
    Sit cSit=is.second;
    int cy=cSit.cy,cx=cSit.cx,mask=cSit.mask,my=cSit.my,mx=cSit.mx;
    if(dp[cy][cx][mask][my][mx]>cval)continue;
    int leftK=K-(my+mx);
    for(int i=0;i<4;i++){
      int ny=cy+dy[i];
      int nx=cx+dx[i];
      if(ny>=0&&nx>=0&&ny<H&&nx<W&&field[ny][nx]!='#'){
        pii p=getNxtMaskAndVal(cy,cx,mask,my,mx,i);
        int nmask=p.first;
        int nAddVal=p.second;
        if(leftK>0&&(i==0||i==3)&&dp[ny][nx][nmask][my+abs(dy[i])][mx+abs(dx[i])]<cval+nAddVal){
          dp[ny][nx][nmask][my+abs(dy[i])][mx+abs(dx[i])]=cval+nAddVal;
          pq.push(make_pair(cval+nAddVal,Sit(ny,nx,nmask,my+abs(dy[i]),mx+abs(dx[i]))));
        }
        else if((i==1||i==2)&&dp[ny][nx][nmask][my][mx]<cval+nAddVal){
          dp[ny][nx][nmask][my][mx]=cval+nAddVal;
          pq.push(make_pair(cval+nAddVal,Sit(ny,nx,nmask,my,mx)));
        }
      }
    }
  }
  int res=0;
  for(int mask=0;mask<(1<<10);mask++)
    for(int i=0;i<3;i++)
      for(int j=0;j<3;j++)
        res=max(res,dp[H-1][W-1][mask][i][j]);
  return res;
}

int main(){
  cin>>H>>W>>K;
  for(int i=0;i<H;i++)
    for(int j=0;j<W;j++)
      cin>>field[i][j];
  memset(dp,-1,sizeof(dp));
  // assert(dfs(0,0,(1<<6),0,0)==dijkstra());
  cout<<dfs(0,0,(1<<6),0,0)<<endl;
  //cout<<dijkstra()<<endl;
  
  return 0;
}

Measured memory_bytes: 209276