// Slower C++ solution:
//AOJ-0558

#include <cstdio>

#include <cstring>

#include <queue>

#include <algorithm>

using namespace std;



char map[1010][1010];

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

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

int vis[1010][1010];

int m, n, N;

struct node{

	int x, y, t;

};



node bfs(int x, int y, char k)

{

	memset(vis, 0, sizeof(vis));

	queue<node> q;

	node s, e, p;

	s = {x, y, 0};

	q.push(s); vis[x][y] = 1;

	while(!q.empty())

	{

		p = q.front(); q.pop();

		if(map[p.x][p.y] == k) return p;

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

		{

			int nx = p.x + dx[i];

			int ny = p.y + dy[i];

			if(nx >= n || nx < 0 || ny >= m || ny < 0 || map[nx][ny] == 'X') continue;

			if(!vis[nx][ny]){

				vis[nx][ny] = 1;

				e = {nx, ny, p.t + 1};

				q.push(e);

			}	

		}

	}

}





int main()

{

	while(~scanf("%d %d %d", &n, &m, &N))

	{

		node s;

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

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

			for(int j = 0; j < m; j++){

			   if(map[i][j] == 'S'){

			   	 s.x = i; s.y = j; s.t = 0;

			   }

			}	

		}

		int ans = 0;

		char c = '0';

		for(char i = 1; i <= N; i++)

		{

			node t = bfs(s.x, s.y, c + i);

			ans += t.t;

			s.x = t.x; s.y = t.y;

		}

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

	}

	return 0; 

}


// Faster C++ solution for the same problem (measured speedup: 5.036647427380008x):
#include <iostream>

#include <queue>

using namespace std;

const int INF = 100000000;

typedef pair<int,int> Point;

Point AllPoint[1000];

int W,H;

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

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

char map[1000][1000];

int deep[1000][1000];

int N;

void BFS(Point Start,Point Over){

    queue<Point> que;

    int FirstDeep = deep[Start.first][Start.second];

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

        for (int j = 0;j<W;j++){

            deep[i][j] = INF;

        }

    }

    que.push(Start);

    deep[Start.first][Start.second] = FirstDeep;

    while (que.size()){

        Point p = que.front();

        que.pop();

        if (p.first== Over.first&&p.second == Over.second)

            break;

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

            int ix = p.first+x[i];

            int iy = p.second+y[i];

            if (ix>=0&&ix<=H

                &&iy>=0&&iy<=W

                &&deep[ix][iy] == INF

                &&map[ix][iy]!='X'){

                que.push(Point(ix,iy));

                deep[ix][iy] = deep[p.first][p.second]+1;

            }

        }

    }

}







int main(){

    cin >> H >> W;

    cin >> N;

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

        for (int j = 0;j<W;j++){

            cin >> map[i][j];

            if ((int)map[i][j]-48>=1&&(int)map[i][j]-48<=N){

                AllPoint[(int)map[i][j]-48].first = i;

                AllPoint[(int)map[i][j]-48].second = j;



            }

            if (map[i][j] == 'S'){

                AllPoint[0].first = i;

                AllPoint[0].second = j;

            }

        }

    }

    deep[AllPoint[0].first][AllPoint[0].second] = 0;

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

        BFS(AllPoint[i],AllPoint[i+1]);

    }

    cout << deep[AllPoint[N].first][AllPoint[N].second]<<endl;



    return 0;

}

//#....

//S.##.

//###G.

//#####

//#####



//#S######.#

//......#..#

//.#.##.##.#

//.#........

//##.##.####

//....#....#

//.#######.#

//....#.....

//.####.###.

//....#...G#