#include <algorithm>
#include <cmath>
#include <climits>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <fstream>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <cassert>
#include <functional>

using namespace std;

#define LOG(...) printf(__VA_ARGS__)
//#define LOG(...)
#define FOR(i,a,b) for(int i=(int)(a);i<(int)(b);++i)
#define REP(i,n) for(int i=0;i<(int)(n);++i)
#define ALL(a) (a).begin(),(a).end()
#define RALL(a) (a).rbegin(),(a).rend()
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())
#define RSORT(c) sort((c).rbegin(),(c).rend())
#define CLR(a) memset((a), 0 ,sizeof(a))
#define WRAP(x,y,w,h) (0<=x && x<w && 0<=y && y<h) 

typedef long long ll;
typedef unsigned long long ull;
typedef vector<bool> vb;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<vb> vvb;
typedef vector<vi> vvi;
typedef vector<vll> vvll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int dx[] = { -1, 0, 1, 0 }; const int dy[] = { 0, 1, 0, -1 };
const int dx2[] = { 1,1,2,1,2,3,1,2,1 }; const int dy2[] = { -2, -1, -1, 0,0,0,1,1,2 };
struct UnionFind {
	vector<int> v;
	UnionFind(int n) : v(n) { for (int i = 0; i < n; i++) v[i] = i; }
	int  find(int x) { return v[x] == x ? x : v[x] = find(v[x]); }
	void unite(int x, int y) { v[find(x)] = find(y); }
};

int main() {
	int w, h;
	while (cin >> w >> h, w) {
		vvi cell(h, vi(w, -1));
		REP(i, h)
			REP(j, w) {
			char c;
			cin >> c;
			if (isdigit(c))
				cell[i][j] = c - '0';
			if (c == 'S' || c == 'T') {
				cell[i][j] = 0;
			}
		}
		map<pair<pair<pii, pii>, bool>, int> G;
		priority_queue<pair<int, pair<pair<pii, pii>, bool>>> Q;
		REP(i, w) {
			if (cell[h - 1][i] == 0) {
				G[{ { {h - 1, i}, { h - 1,i }}, false}] = 0;
				G[{ { {h - 1, i}, { h - 1,i }}, true}] = 0;
				Q.push({ 0,{{ { h - 1, i },{ h - 1,i } },false } });
				Q.push({ 0,{ { { h - 1, i },{ h - 1,i } },true } });
			}
		}
		int clear = -1;
		while (!Q.empty()) {
			pair<int, pair<pair<pii, pii>, bool>> q = Q.top();Q.pop();
			q.first *= -1;
			int ly = q.second.first.first.first;
			int lx = q.second.first.first.second;
			int ry = q.second.first.second.first;
			int rx = q.second.first.second.second;
			bool lreg = q.second.second;
			if ((ly == 0 && cell[ly][lx] == 0) || (ry == 0 && cell[ry][rx] == 0)) {
				clear = q.first;
				break;
			}

			REP(i, 9) {
				int nly = ly;
				int nlx = lx;
				int nry = ry;
				int nrx = rx;
				if (lreg) {
					nry = ly + dy2[i];
					nrx = lx + dx2[i];
				}
				else {
					nly = ry + dy2[i];
					nlx = rx - dx2[i];
				}
				if (WRAP(nlx, nly, w, h) && WRAP(nrx, nry, w, h) && cell[nly][nlx] != -1 && cell[nry][nrx] != -1) {
					if ((G.find({ { {nly,nlx} , {nry,nrx} },!lreg }) == G.end())
						|| (G.find({ { { nly,nlx } ,{ nry,nrx } },!lreg }) != G.end() && G[{ { {nly, nlx}, { nry,nrx } }, !lreg }] > q.first + (!lreg ? cell[nly][nlx] : cell[nry][nrx]))) {
						G[{ { {nly, nlx}, { nry,nrx } }, !lreg }] = q.first + (!lreg ? cell[nly][nlx] : cell[nry][nrx]);
						Q.push({ -q.first - (!lreg ? cell[nly][nlx] : cell[nry][nrx]),{ { { nly,nlx } ,{ nry,nrx } },!lreg } });
					}
				}
			}
		}
		cout << clear << endl;
	}
}

Measured memory_bytes: 4444