#include<bits/stdc++.h>
using namespace std;
const int inf=0x3f3f3f3f;
int main()
{
	ios_base::sync_with_stdio(false);
	int r,c;
	cin>>r>>c;
	vector<string> a(r+5);
	vector<int> dx={0,1,0,-1},dy={1,0,-1,0};
	vector<vector<vector<int>>> go(r+5,vector<vector<int>>(c+5,vector<int>(5)));
	for(int i=1;i<=r;i++)
	{
		string s;
		cin>>s;
		a[i]=' '+s;
	}
	for(int i=1;i<=r;i++)
	{
		for(int j=1;j<=c;j++)
		{
			if(i>1)
			{
				if(a[i][j]!=a[i-1][j])
					go[i][j][3]=1;
				else
					go[i][j][3]=(go[i-1][j][3]==0?0:go[i-1][j][3]+1);
			}
			if(j>1)
			{
				if(a[i][j]!=a[i][j-1])
					go[i][j][2]=1;
				else
					go[i][j][2]=(go[i][j-1][2]==0?0:go[i][j-1][2]+1);
			}
			
		}
	}
	for(int i=r;i>=1;i--)
	{
		for(int j=c;j>=1;j--)
		{
			if(i<r)
			{
				if(a[i][j]!=a[i+1][j])
					go[i][j][1]=1;
				else
					go[i][j][1]=(go[i+1][j][1]==0?0:go[i+1][j][1]+1);
			}
			if(j<c)
			{
				if(a[i][j]!=a[i][j+1])
					go[i][j][0]=1;
				else
					go[i][j][0]=(go[i][j+1][0]==0?0:go[i][j+1][0]+1);
			}
			
		}
	}
	string s;
	cin>>s;
	int n=(int)s.length()+1;
	s=' '+s+'*';
	vector<vector<vector<int>>> dis(n+5,vector<vector<int>>(r+5,vector<int>(c+5,inf)));
	dis[0][1][1]=0;
	queue<tuple<int,int,int>> q;
	q.emplace(0,1,1);
	while(not q.empty())
	{
		auto [pos,x,y]=q.front();q.pop();
		for(int d=0;d<4;d++)
		{
			if(go[x][y][d])
			{
				int nx=x+dx[d]*go[x][y][d],ny=y+dy[d]*go[x][y][d];
				if(dis[pos][nx][ny]>dis[pos][x][y]+1)
				{
					dis[pos][nx][ny]=dis[pos][x][y]+1;
					q.emplace(pos,nx,ny);
				}
			}
		}
		if(s[pos+1]==a[x][y])
		{
			if(dis[pos+1][x][y]>dis[pos][x][y]+1)
			{
				dis[pos+1][x][y]=dis[pos][x][y]+1;
				q.emplace(pos+1,x,y);
			}
		}
	}
	int ans=inf;
	for(int x=1;x<=r;x++)
		for(int y=1;y<=c;y++)
			ans=min(ans,dis[n][x][y]);
	cout<<ans<<endl;
	return 0;
}