#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);
			}
		}
	}
}
vector<PII> poses[N * N];

void calc(int n, int m, int idx){
	FOR(i, 0, N * N)
		poses[i].clear();
		
	int mn = dp[idx - 1][0][0];
	FOR(i, 0, n){
		FOR(j, 0, m){
			dp[idx][i][j] = dp[idx - 1][i][j];
			mn = min(mn, dp[idx][i][j]);
		}
	}
	FOR(i, 0, n){
		FOR(j, 0, m){
			if(dp[idx][i][j] >= mn + N * N)
				continue;
			poses[dp[idx][i][j] - mn].PB(MP(i,j));
		}
	}
	FOR(i, 0, N * N){
		for(auto [x, y] : poses[i]){
			if(dp[idx][x][y] - mn < i)
				continue;
			
			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){
					dp[idx][nx][ny] = dp[idx][x][y] + 1;
					
					assert(i + 1 < N * N);
					poses[i + 1].PB(MP(nx, 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;
}