// Slower C++ solution:
//

//  AOJ 0558 Chees

//

//  Created by TaoSama on 2015-02-20

//  Copyright (c) 2014 TaoSama. All rights reserved.

//

#include <algorithm>

#include <cctype>

#include <cmath>

#include <cstdio>

#include <cstdlib>

#include <cstring>

#include <iomanip>

#include <iostream>

#include <map>

#include <queue>

#include <string>

#include <set>

#include <vector>

#define CLR(x,y) memset(x, y, sizeof(x))



using namespace std;

const int INF = 0x3f3f3f3f;

const int MOD = 1e9 + 7;

const int N = 1e5 + 10;



struct Point {

	int x, y;

	Point(int x = 0, int y = 0): x(x), y(y) {}

} c[15];

int n, m, k, dp[1005][1005];

int d[4][2] = { -1, 0, 1, 0, 0, 1, 0, -1};

char a[1005][1005];



int bfs(int x) {

	memset(dp, 0x3f, sizeof dp);

	queue <Point> q; q.push(c[x - 1]);

	dp[c[x - 1].x][c[x - 1].y] = 0;

	while(!q.empty()) {

		Point cur = q.front(); q.pop();

		for(int i = 0; i < 4; ++i) {

			Point nxt(cur.x + d[i][0], cur.y + d[i][1]);

			if(nxt.x < 1 || nxt.x > n || nxt.y < 1 || nxt.y > m

			        || a[nxt.x][nxt.y] == 'X') continue;

			if(dp[nxt.x][nxt.y] == INF) {

				dp[nxt.x][nxt.y] = dp[cur.x][cur.y] + 1;

				q.push(nxt);

			}

		}

	}

	return dp[c[x].x][c[x].y];

}

int main() {

#ifdef LOCAL

	freopen("in.txt", "r", stdin);

//	freopen("out.txt","w",stdout);

#endif

	ios_base::sync_with_stdio(0);



	while(cin >> n >> m >> k) {

		for(int i = 1; i <= n; ++i) {

			for(int j = 1; j <= m; ++j) {

				cin >> a[i][j];

				if(a[i][j] == 'S')

					c[0].x = i, c[0].y = j;

				if(isdigit(a[i][j]))

					c[a[i][j] - '0'].x = i, c[a[i][j] - '0'].y = j;

			}

		}

		int ans = 0;

		for(int i = 1; i <= k; ++i)

			ans += bfs(i);

		cout << ans << endl;

	}

	return 0;

}

// Faster C++ solution for the same problem (measured speedup: 5.1124819249843165x):
#include <iostream>

#include <cstdio>

//#include <cmath>

#include <vector>

#include <cstring>

#include <string>

#include <algorithm>

#include <string>

#include <set>

#include <functional>

#include <numeric>

#include <sstream>

#include <stack>

#include <map>

#include <queue>



#define CL(arr, val)    memset(arr, val, sizeof(arr))



#define ll long long

#define inf 0x7f7f7f7f

#define lc l,m,rt<<1

#define rc m + 1,r,rt<<1|1

#define pi acos(-1.0)



#define L(x)    (x) << 1

#define R(x)    (x) << 1 | 1

#define MID(l, r)   (l + r) >> 1

#define Min(x, y)   (x) < (y) ? (x) : (y)

#define Max(x, y)   (x) < (y) ? (y) : (x)

#define E(x)        (1 << (x))

#define iabs(x)     (x) < 0 ? -(x) : (x)

#define OUT(x)  printf("%I64d\n", x)

#define lowbit(x)   (x)&(-x)

#define Read()  freopen("a.txt", "r", stdin)

#define Write() freopen("dout.txt", "w", stdout);

#define maxn 1000000000

#define N 1010

using namespace std;



int h,w,x;

int dir[4][2]={-1,0,0,1,0,-1,1,0};

typedef pair<int,int> P;

P p;

char maze[N][N];

int d[N][N];



int bfs(char c)

{

    queue<P>que;

    for(int i=0;i<h;i++)

        for(int j=0;j<w;j++) d[i][j]=maxn;

    que.push(p);

    d[p.first][p.second]=0;

    P p1,p2;

    while(que.size())

    {

        p1=que.front(); que.pop();

        if(maze[p1.first][p1.second]==c)

        {

            p=p1; break;

        }

        for(int i=0;i<4;i++)

        {

            p2.first=p1.first+dir[i][0];

            p2.second=p1.second+dir[i][1];

            if(p2.first>=0&&p2.first<h&&p2.second>=0&&p2.second<w&&maze[p2.first][p2.second]!='X'&&d[p2.first][p2.second]==maxn)

            {

                que.push(p2);

                d[p2.first][p2.second]=d[p1.first][p1.second]+1;

            }

        }

    }

    return d[p.first][p.second];

}



int main()

{

    //freopen("a.txt","r",stdin);

    while(~scanf("%d%d%d",&h,&w,&x))

    {

        getchar();

        int sum=0;

        for(int i=0;i<h;i++)

        {

            scanf("%s",maze[i]);

            //printf("%s\n",maze[i]);

            for(int j=0;j<w;j++)

            {

                if(maze[i][j]=='S')

                {

                    p.first=i;

                    p.second=j;

                }

            }

        }

        //printf("%d %d\n",p1.first,p1.second);

        for(int i=1;i<=x;i++)

        {

            sum+=bfs('0'+i);

        }

        printf("%d\n",sum);

    }

   return 0;

}