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

typedef long long ll;
typedef vector<int> vint;
typedef vector<long long> vll;
typedef pair<int,int> pint;
typedef pair<long long, long long> pll;

#define MP make_pair
#define PB push_back
#define ALL(s) (s).begin(),(s).end()
#define EACH(i, s) for (__typeof__((s).begin()) i = (s).begin(); i != (s).end(); ++i)
#define COUT(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << endl

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
template<class T1, class T2> ostream& operator << (ostream &s, pair<T1,T2> P) 
{ return s << '<' << P.first << ", " << P.second << '>'; }
template<class T> ostream& operator << (ostream &s, vector<T> P) 
{ for (int i = 0; i < P.size(); ++i) { if (i > 0) { s << " "; } s << P[i]; } return s; }
template<class T1, class T2> ostream& operator << (ostream &s, map<T1,T2> P) 
{ EACH(it, P) { s << "<" << it->first << "->" << it->second << "> "; } return s; }


int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};

int ch[4][4][12] = {
    {
        {-1, -1, 0, -1, 1, 2, -1, 3, 4, 5, -1, -1}, 
        {-1, -1, 1, -1, 3, 4, -1, 6, 7, 8, -1, -1}, 
        {0, 2, 3, 5, 6, 7, -1, 9, 10, 11, -1, -1}, 
        {-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, -1, -1}
    },
    {
        {-1, -1, -1, 0, 1, -1, 2, 3, 4, 5, 6, 7}, 
        {-1, 0, -1, 2, 3, -1, 5, 6, 7, -1, 9, 10}, 
        {0, 1, 3, 4, 5, -1, 7, 8, 9, -1, 10, 11}, 
        {-1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
    },
    {
        {-1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 7, 8}, 
        {-1, 0, 1, -1, 3, 4, 5, -1, 7, 8, -1, 10}, 
        {0, 1, 2, -1, 4, 5, 6, -1, 7, 8, -1, 9}, 
        {-1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8}
    },
    {
        {-1, -1, -1, -1, 0, 1, 2, 4, 5, 7, -1, -1}, 
        {-1, 0, 1, 2, -1, 4, 5, -1, 7, -1, -1, -1}, 
        {-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1}, 
        {-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1}
    }
};
    
int pl[4] = {9, 7, 4, 0};

int npl[4][4] = {
    {-1, -1, 5, 8},
    {11, 8, 3, 6},
    {8, 5, 0, 3},
    {4, 1, -1, -1}
};

int n, m, K;
string fi[55];


int dp[53][53][5][4100];

int main() {
    //freopen( "/Users/macuser/Dropbox/Contest/input.in", "r", stdin );
    while (cin >> n >> m >> K) {
        for (int i = 0; i < n; ++i) cin >> fi[i];
        
        int res = 0;
        
        memset(dp, -1, sizeof(dp));
        dp[0][0][0][(1<<9)] = 0;
        for (int k = 0; k <= K; ++k) {
            for (int i = 0; i < n; ++i) {
                for (int j = 0; j < m; ++j) {
                    for (int bit = 0; bit < (1<<12); ++bit) {
                        if (dp[i][j][k][bit] == -1) continue;
                        if (i == n-1 && j == m-1) chmax(res, dp[i][j][k][bit]);
                        
                        //cout << i << ", " << j << ", " << k << " ; " << bitset<12>(bit) << " : " << dp[i][j][k][bit] << endl;
                        
                        for (int l = 0; l <= 3; ++l) {
                            int ni = i + dx[l], nj = j + dy[l];
                            if (ni < 0 || ni >= n || nj < 0 || nj >= m) continue;
                            if (fi[ni][nj] == '#') continue;
                            
                            int add = 0;
                            if (fi[ni][nj] != '.') add = fi[ni][nj] - '0';
                            if (npl[k][l] != -1)
                                if (bit & (1<<npl[k][l]))
                                    add = 0;
                            
                            int nk = k;
                            if (l == 2 || l == 3) ++nk;
                            if (nk > K) continue;
                            
                            int nbit = 0;
                            for (int b = 0; b < 12; ++b)
                                if (bit & (1<<b))
                                    if (ch[k][l][b] != -1)
                                        nbit |= (1<<ch[k][l][b]);
                            
                            nbit |= (1<<pl[nk]);
                            
                            chmax(dp[ni][nj][nk][nbit], dp[i][j][k][bit] + add);
                        }
                    }
                }
            }
        }

        cout << res << endl;
    }
    return 0;
}
