#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pi;
typedef pair<ll, ll> pl;
typedef pair<ld, ld> pd;

typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;

#define FOR(i, a, b) for (int i = a; i < (b); i++)
#define F0R(i, a) for (int i = 0; i < (a); i++)
#define FORd(i, a, b) for (int i = (b) - 1; i >= (a); i--)
#define F0Rd(i, a) for (int i = (a) - 1; i >= 0; i--)
#define trav(a, x) for (auto &a : x)
#define sz(x) (int)(x).size()
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()
#define ins insert

const char nl = '\n';

int dx[4] = {1,0,-1,0};
int dy[4] = {0,1,0,-1};
int N, M;
bool ok(int x, int y) {
    return x >= 0 && y >= 0 && x < N && y < M;
}
vpi nxt[51][51];
string S[51];
string T;

int dist[51][51];

const int INF = 1e8;

void prop() {
    priority_queue<pair<int, pi>, vector<pair<int, pi>>, greater<pair<int, pi>>> q;
    F0R(i, N) F0R(j, M) {
        if (dist[i][j] == INF) continue;
        q.push({dist[i][j], {i, j}});
    }
    while (!q.empty()) {
        auto val = q.top(); q.pop();
        int d = val.f;
        int x = val.s.f, y = val.s.s;
        if (d != dist[x][y]) continue;
        trav(a, nxt[x][y]) {
            if (dist[a.f][a.s] > dist[x][y] + 1) {
                dist[a.f][a.s] = dist[x][y] + 1;
                q.push({dist[a.f][a.s], a});
            }
        }
    }
}

void solve() {
    cin >> N >> M;
    F0R(i, N) cin >> S[i];
    cin >> T;
    F0R(i, N) F0R(j, M) dist[i][j] = INF;
    dist[0][0] = 0;

    F0R(i, N) {
        F0R(j, M) {
            F0R(k, 4) {
                int x = i, y = j;
                while (ok(x, y) && S[x][y] == S[i][j]) {
                    x += dx[k], y += dy[k];
                }
                if (ok(x, y)) {
                    nxt[i][j].pb({x, y});
                }
            }
        }
    }

    T += '*';
    trav(a, T) {
        prop();
        F0R(i, N) {
            F0R(j, M) {
                if (S[i][j] != a) {
                    dist[i][j] = INF;
                }
            }
        }
        int cur = INF;
        F0R(i, N) F0R(j, M) cur = min(cur, dist[i][j]);
    }
    int ans = INF;
    F0R(i, N) F0R(j, M) ans = min(ans, dist[i][j]);
    cout << ans+sz(T) << endl;

}

int main() {
	ios_base::sync_with_stdio(0); cin.tie(0);
	solve();
	return 0;
}