#pragma GCC optimize(3,"Ofast","inline")
#include <bits/stdc++.h>
using namespace std;
inline int read()
{
	char ch=getchar();
	int x=0,m=1;
	while(!isdigit(ch)){
		if (ch=='-') m=-1;
		ch=getchar();
	}
	while(isdigit(ch)){
		x=x*10+ch-'0';
		ch=getchar();
	}
	return x*m;
}
inline void write(int x)
{
	if (x<0) putchar('-'),x=-x;
	if (x>9) write(x/10);
	putchar(x%10+'0');
}
int n,m;
struct Node{
	int x,y,z;
}f[10010];
short dx[5]={0,0,0,1,-1},dy[5]={0,1,-1,0,0};
bool p[110][110];
inline int bfs(int x1,int y1,int x,int y)
{
	int h(0),t(1);
	f[1].x=x1;f[1].y=y1;
	while(h<t){
		++h;
		if (f[h].x==x&&f[h].y==y) return f[h].z;
		for (int i=1;i<=4;i++){
			int xx(dx[i]+f[h].x),yy(dy[i]+f[h].y);
			if (p[xx][yy]==false) continue;
			f[++t].x=xx;
			f[t].y=yy;
			f[t].z=f[h].z+1;
		}
	}
	return -1;
}
signed main()
{
	n=read(),m=read();
	char ch(getchar());
	int x1,y1,x2,y2;
	for (int i=1;i<=n;i++) for (int j=1;j<=m;j++){
		while(ch!='S'&&ch!='T'&&ch!='.'&&ch!='#') ch=getchar();
		if (ch=='S') x1=i,y1=j,p[i][j]=true;
		else if (ch=='T') x2=i,y2=j,p[i][j]=true;
		else if (ch=='.') p[i][j]=true;
		ch=getchar();
	}
	write(bfs(x1,y1,x2,y2));
	return 0;
}