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

#include <cstdio>

#include <cstring>

#include <cmath>

#include <vector>

#include <queue>

#include <set>

#include <map>

#include <stack>

#include <utility>

#include <algorithm>

#include <sstream>

using namespace std;

typedef pair<int,int> P;



const int max_n=1000+10;

int h,w,n,sx,sy,dx[]={0,0,-1,1},dy[]={-1,1,0,0},d[max_n][max_n],ans;

char c[max_n][max_n];



void bfs(int x,int y,int m){

	if(m>n)return;

	queue<P> q;

	memset(d,0,sizeof(d));

	q.push(P(x,y));

	d[x][y]=1;

	while(!q.empty()){

		P p=q.front();

		q.pop();

		if(c[p.first][p.second]=='0'+m){

		    ans+=d[p.first][p.second]-1;

		    bfs(p.first,p.second,m+1);

		    return;

		}

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

			int tx=p.first+dx[i],ty=p.second+dy[i];

			if(tx>=0 && tx<h && ty>=0 && ty<w && c[tx][ty]!='X' && !d[tx][ty]){

				q.push(P(tx,ty));

				d[tx][ty]=d[p.first][p.second]+1;

			}

		}

	}

}



int main(){

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

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

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

            cin>>c[i][j];

            if(c[i][j]=='S'){sx=i;sy=j;}

        }

    bfs(sx,sy,1);

    cout<<ans<<endl;

    return 0;

}

// Faster C++ solution for the same problem (measured speedup: 5.129687589402425x):
#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#