#include<iostream>
#include<cstring>
#include<string>
using namespace std;
string s[1001];
int n,m,a[1001][1001],v,w,h[100001][4],dx[5]={0,-1,0,1,0},dy[5]={0,0,1,0,-1};
void bfs(int x,int y)
{
	int head=0,tail=1,nx,ny,i;
	h[1][1]=x;
	h[1][2]=y;
	h[1][3]=0;
	while(head<tail)
	{
		head++;
		for(i=1;i<=4;i++)
		{
			nx=h[head][1]+dx[i];
			ny=h[head][2]+dy[i];
			if(nx>=1&&nx<=m&&ny>=1&&ny<=n&&a[nx][ny]==-1)
			{
				tail++;
				h[tail][1]=nx;
				h[tail][2]=ny;
				h[tail][3]=h[head][3]+1;
				a[nx][ny]=h[tail][3];
			}
		}
	}
}
int main()
{
	memset(a,-1,sizeof(a));
	int i,j,x,y;
	cin>>n>>m;
	for(i=1;i<=n;i++)
	{
		cin>>s[i];
		for(j=0;j<m;j++)
		{
			if(s[i][j]=='#')
				a[i][j+1]=0;
			if(s[i][j]=='S')
			{
				x=i;
				y=j+1;
				a[i][j+1]=0;
			}
			if(s[i][j]=='T') 
			{
				v=i;
				w=j+1;
			}
		}
	}
	bfs(x,y);
	cout<<a[v][w]<<endl;
	return 0;
}

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