#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <queue>
using namespace std;

struct node {
	int x, y, num, step;
};

const int direct[4][2] = {{-1, 0}, {0, -1}, {1, 0}, {0, 1}};
const int MAXN = 60;
const int MAXM = 1e4 + 10;
const int INF = 1e9 + 10;
int r, c, minn[MAXN][MAXN][MAXM], len, ans;
char Map[MAXN][MAXN], str[MAXM];
queue<node> q;

bool illegal(int x, int y) {
	if (1 <= x && x <= r && 1 <= y && y <= c) return true;
	return false;
}

void bfs() {
	int cnt = 0;
	while (Map[1][1] == str[cnt + 1]) cnt++;
	q.push((node){1, 1, cnt, 0});
	minn[1][1][cnt] = 0;
	while (!q.empty()) {
		node p = q.front();
		if (p.num == len) {
			ans = p.step;
			return;
		}
		q.pop();
		for (int i = 0; i < 4; i++) {
			int nx = p.x + direct[i][0], ny = p.y + direct[i][1];
			while (illegal(nx, ny) && Map[nx][ny] == Map[p.x][p.y]) {
				nx += direct[i][0];
				ny += direct[i][1];
			}
			if (illegal(nx, ny)) {
				if (Map[nx][ny] == str[p.num + 1]) {
					if (minn[nx][ny][p.num + 1] > p.step + 2) {
						minn[nx][ny][p.num + 1] = p.step + 1;
						q.push((node){nx, ny, p.num + 1, p.step + 2});
					}
				} else {
					if (minn[nx][ny][p.num] > p.step + 1) {
						minn[nx][ny][p.num] = p.step + 1;
						q.push((node){nx, ny, p.num, p.step + 1});
					}
				}
			}
		}
	}
} 

int main() {
	cin >> r >> c;
	for (int i = 1; i <= r; i++) {
		for (int j = 1; j <= c; j++)
			cin >> Map[i][j];
	}
	cin >> (str + 1);
	len = strlen(str + 1);
	str[len + 1] = '*';
	len++;
	for (int i = 1; i <= r; i++) {
		for (int j = 1; j <= c; j++) {
			for (int k = 0; k < MAXM; k++) {
				minn[i][j][k] = INF;
			}
		} 
	}
	bfs();
	cout << ans << endl;
	return 0;
}