import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.io.IOException;
import java.util.Queue;
import java.util.LinkedList;
import java.util.NoSuchElementException;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author Seikichi KONDO (seikichi@kmc.gr.jp)
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        FastScanner in = new FastScanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        AOJ0558 solver = new AOJ0558();
        solver.solve(1, in, out);
        out.close();
    }

    static final class AOJ0558 {
        @SuppressWarnings("unused")
        public void solve(int testNumber, FastScanner in, PrintWriter out) {
            final int H = in.nextInt(), W = in.nextInt(), N = in.nextInt();

            char[][] map = new char[H][];
            for (int i = 0; i < H; i++) {
                map[i] = in.next().toCharArray();
            }

            // solve
            int result = 0;
            for (int i = 0; i < N; i++) {
                int sy = -1, sx = -1;
                findStartPosition:
                {
                    final char start = i == 0 ? 'S' : (char) ('0' + i);
                    for (int y = 0; y < H; y++) {
                        for (int x = 0; x < W; x++) {
                            if (map[y][x] == start) {
                                sy = y;
                                sx = x;
                            }
                        }
                    }
                }
                final Queue<Pair<Integer, Integer>> que = new LinkedList<Pair<Integer, Integer>>();
                final int[][] dist = new int[H][W];
                for (int j = 0; j < H; j++) {
                    Arrays.fill(dist[j], -1);
                }
                dist[sy][sx] = 0;
                que.add(Pair.of(sy, sx));

                int[][] delta = {{+1, 0}, {0, +1}, {-1, 0}, {0, -1}};
                while (!que.isEmpty()) {
                    final Pair<Integer, Integer> p = que.remove();
                    final int y = p.first(), x = p.second();
                    if (map[y][x] == (char) ('1' + i)) {
                        result += dist[y][x];
                        break;
                    }

                    for (int[] d : delta) {
                        final int ny = y + d[0];
                        final int nx = x + d[1];
                        if (ny < 0 || H <= ny || nx < 0 || W <= nx || map[ny][nx] == 'X' || dist[ny][nx] != -1) {
                            continue;
                        }
                        dist[ny][nx] = 1 + dist[y][x];
                        que.add(Pair.of(ny, nx));
                    }
                }
            }
            out.println(result);
        }

    }

    static final class Pair<F, S> {
        private final F first;
        private final S second;

        public static <F, S> Pair<F, S> of(F first, S second) {
            return new Pair<F, S>(first, second);
        }

        private Pair(F first, S second) {
            this.first = first;
            this.second = second;
        }

        public F first() {
            return this.first;
        }

        public S second() {
            return this.second;
        }

    }

    static final class FastScanner {
        private final InputStream in;
        private final byte[] buffer = new byte[1024];
        private int ptr = 0;
        private int buflen = 0;

        public FastScanner(InputStream in) {
            this.in = in;
        }

        private boolean hasNextByte() {
            if (ptr < buflen) {
                return true;
            } else {
                ptr = 0;
                try {
                    buflen = in.read(buffer);
                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (buflen <= 0) {
                    return false;
                }
            }
            return true;
        }

        private int readByte() {
            if (hasNextByte()) return buffer[ptr++];
            else return -1;
        }

        private static boolean isPrintableChar(int c) {
            return 33 <= c && c <= 126;
        }

        private void skipUnprintable() {
            while (hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;
        }

        public boolean hasNext() {
            skipUnprintable();
            return hasNextByte();
        }

        public String next() {
            if (!hasNext()) throw new NoSuchElementException();
            StringBuilder sb = new StringBuilder();
            int b = readByte();
            while (isPrintableChar(b)) {
                sb.appendCodePoint(b);
                b = readByte();
            }
            return sb.toString();
        }

        public int nextInt() {
            if (!hasNext()) throw new NoSuchElementException();
            int n = 0;
            boolean minus = false;
            int b = readByte();
            if (b == '-') {
                minus = true;
                b = readByte();
            }
            if (b < '0' || '9' < b) {
                throw new NumberFormatException();
            }
            while (true) {
                if ('0' <= b && b <= '9') {
                    n *= 10;
                    n += b - '0';
                } else if (b == -1 || !isPrintableChar(b)) {
                    return minus ? -n : n;
                } else {
                    throw new NumberFormatException();
                }
                b = readByte();
            }
        }

    }
}

Measured memory_bytes: 104344