#include <bits/stdc++.h>
using namespace std;

#define SZ(a) (int)a.size()
#define ALL(a) a.begin(), a.end()
#define FOR(i, a, b) for (int i = (a); i<(b); ++i)
#define RFOR(i, b, a) for (int i = (b)-1; i>=(a); --i)
#define MP make_pair
#define PB push_back
#define F first
#define S second
#define FILL(a, b) memset(a, b, sizeof(a))

typedef long long LL;
typedef pair<int, int> PII;
typedef vector<int> VI;

const int N = 52;
const int MAX = 10047;
const int INF = 1e9 + 47;

int dp[MAX][N][N];
char c[N][N];

PII moves[N][N][4];

int dx[4] = {0, 0, -1, 1};
int dy[4] = {-1, 1, 0, 0};

bool ok(int x){
	return 0 <= x && x < N;
}

void prec(){
	FOR(i, 0, N){
		FOR(j, 0, N){
			FOR(t, 0, 4){
				int ni = i, nj = j;
				while(ok(ni) && ok(nj) && c[i][j] == c[ni][nj]){
					ni += dx[t];
					nj += dy[t];
				}
				if(ok(ni) && ok(nj))
					moves[i][j][t] = MP(ni, nj);
				else
					moves[i][j][t] = MP(-1, -1);
			}
		}
	}
}

void calc(int n, int m, int idx){
	set<pair<int, int>> q;
	FOR(i, 0, n){
		FOR(j, 0, m){
			dp[idx][i][j] = dp[idx - 1][i][j];
			q.insert(MP(dp[idx][i][j], i * N + j));
		}
	}
	while(SZ(q)){
		auto [dist, i] = *q.begin();
		q.erase(q.begin());
		
		int x = i / N;
		int y = i % N;
		
		FOR(t, 0, 4){
			if(moves[x][y][t] == MP(-1, -1))
				continue;
			auto [nx, ny] = moves[x][y][t];
			if(nx >= n || ny >= m)
				continue;
				
			if(dp[idx][nx][ny] > dp[idx][x][y] + 1){
				q.erase(MP(dp[idx][nx][ny], nx * N + ny));
				
				dp[idx][nx][ny] = dp[idx][x][y] + 1;
				
				q.insert(MP(dp[idx][nx][ny], nx * N + ny));				
			}
		}
	}
}

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	
	FOR (i, 0, N) FOR (j, 0, N) c[i][j] = 'a';
	
	int n, m;
	cin >> n >> m;
	FOR (i, 0, n) FOR (j, 0, m) cin >> c[i][j];
	
	prec();
/*	FOR(i, 0, n){
		FOR(j, 0, m){
			FOR(t, 0, 4)
				cout << moves[i][j][t].F << " " << moves[i][j][t].S << "\n";
			cout << "\n";
		}
		
	}*/
	
	FOR (t, 0, MAX) FOR (i, 0, N) FOR (j, 0, N) dp[t][i][j] = INF;
	dp[0][0][0] = 0;
	
	string s;
	cin >> s;
	s += '*';
	FOR (step, 0, SZ(s))
	{
		calc(n, m, step + 1);
				
		FOR (i, 0, N)
		{
			FOR (j, 0, N)
			{
				if (c[i][j] != s[step])
					dp[step + 1][i][j] = INF;
				//cout << dp[step + 1][i][j] << " ";
			}
		//	cout << endl;
		}
	}
	int ans = INF;
	FOR (i, 0, n) FOR (j, 0, m) ans = min(ans, dp[SZ(s)][i][j]);
	cout << ans + SZ(s) << '\n';
	return 0;
}