#include <cstdio>
#include <cstring>
#include <utility>
#include <functional>
#include <queue>
#define rep(i,n) for(int i=0;i<n;++i)
#define rrep(i,n) for(int i=1;i<=n;++i)
#define x first
#define y second
#define eb emplace_back
using namespace std;
using pp=pair<int,int>;
int n, m, k;
char q[510][510];
pp e[510][510][4];
pp il[10];
int dp[510][510][50];
bool vis[510][510][50];
const int dx[5] = {0, 1, 0, -1}, *dy = dx+1;
pp E(int x, int y, int d) {
pp &ret = e[x][y][d];
if (ret.x) return ret;
int nx=x+dx[d], ny=y+dy[d];
if (1<=nx && nx<=n && 1<=ny && ny<=m && q[nx][ny]!='x') {
switch(q[nx][ny]) {
case 'A': ret = E(nx, ny, (d+3)%4); break;
case 'C': ret = E(nx, ny, (d+1)%4); break;
default: ret = E(nx, ny, d); break;
}
return ret;
} else return ret={x, y};
}
int C[10][10];
using t3=tuple<int,int,int>;
t3 qv[250010];
int st[250010];
int nxt[250010];
int nn;
int main()
{
scanf("%d%d%d",&k,&m,&n);
rrep(i, n) {
scanf("%s", q[i]+1);
rrep(j, m) if ((q[i][j]&48)==48) il[q[i][j]-48]={i,j};
}
{ static int p = 0; rrep(i, k) rrep(j, i) C[j][i] = ++p; }
const int inf = 1e9;
rrep(len, k) {
nn = 0;
rrep(i, n) rrep(j, m) rrep(l, k-len+1) {
int r = l+len-1;
int p = C[l][r];
int me = inf;
if (len == 1 && q[i][j]>=48 && q[i][j]<58 && l == q[i][j]-48) me = 0;
else for(int t=l; t<r; ++t) {
int v = dp[i][j][C[l][t]]+
dp[i][j][C[t+1][r]];
if (v >= inf) continue;
if (v < me) me = v;
}
dp[i][j][p] = me;
if (me != inf) {
int x = ++nn; qv[x] = {i, j, l};
if (!st[me]) st[me] = x;
else nxt[x] = st[me], st[me] = x;
}
}
if (len == k) break;
for(int ans=0; ans<n*m; st[ans]=0, ++ans) for(int v=st[ans]; v; ) {
int x,y,l,u;
tie(x,y,l) = qv[v]; u = nxt[v]; nxt[v] = 0; v = u;
int p = C[l][l+len-1];
if (dp[x][y][p] != ans) continue;
rep(d, 4) {
pp t = E(x, y, d);
if (t == pp(x, y)) continue;
if (dp[t.x][t.y][p] > ans+1) {
dp[t.x][t.y][p] = ans+1;
int x = ++nn; qv[x] = {t.x, t.y, l};
if (!st[ans+1]) st[ans+1]=x;
else nxt[x]=st[ans+1], st[ans+1]=x;
}
}
}
}
int ans = inf;
rrep(i, n) rrep(j, m)
ans = min(ans, dp[i][j][C[1][k]]);
if (ans == inf) ans = -1;
printf("%d\n", ans);
return 0;
}
