// Slower C++ solution:
#include<cstdio>

#include<cstring>

#include<queue>

#define maxn 1002

#define maxc 10

using namespace std;

struct point{

    int r,c;

};

char graph[maxn][maxn];

int len[maxn][maxn];

bool mark[maxn][maxn];

point node[maxc];

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

int main(void){

    int h,w,cheese,tr,tc,answer=0;

    scanf("%d%d%d",&h,&w,&cheese);

    memset(graph,0,sizeof(graph));

    memset(node,0,sizeof(node));

    for(int i=1;i<=h;i++) for(int j=1;j<=w;j++){

        do scanf("%c",&graph[i][j]);

        while(graph[i][j]==' ' || graph[i][j]=='\n');

        if(graph[i][j]>='0' && graph[i][j]<='9'){

            node[graph[i][j]-'0'].r=i;

            node[graph[i][j]-'0'].c=j;

        }

        else if(graph[i][j]=='S'){

            node[0].r=i;

            node[0].c=j;

        }

    }

    for(int cnt=0;cnt<cheese;cnt++){

        memset(len,0,sizeof(len));

        memset(mark,false,sizeof(mark));

        for(int i=0;i<=h+1;i++){mark[i][0]=true;mark[i][w+1]=true;}

        for(int j=0;j<=w+1;j++){mark[0][j]=true;mark[h+1][j]=true;}

        queue<point> q;

        q.push(node[cnt]);

        len[node[cnt].r][node[cnt].c]=0;

        point ongo,togo;

        while(!q.empty()){

            ongo=q.front();

            q.pop();

            if(mark[ongo.r][ongo.c]) continue;

            mark[ongo.r][ongo.c]=true;

            if(ongo.r==node[cnt+1].r && ongo.c==node[cnt+1].c){

                answer+=len[ongo.r][ongo.c];

                break;

            }

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

                togo.r=ongo.r+dir[i][0];togo.c=ongo.c+dir[i][1];

                if(mark[togo.r][togo.c]==false && graph[togo.r][togo.c]!='X'){

                    len[togo.r][togo.c]=len[ongo.r][ongo.c]+1;

                    q.push(togo);

                }

            }

        }

    }

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

    return 0;

}


// Faster C++ solution for the same problem (measured speedup: 7.076711046663816x):
#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#