BEGIN {
	FS = "";
	y = 1;
}
function elev(a) {
	return index("abcdefghijklmnopqrstuvwxyz", a);
}
{
	for (x = 1; x <= NF; ++x) {
		if ($x == "S") {
			S = x "," y;
			m[x,y] = elev("a");
		} else if ($x == "E") {
			E = x "," y;
			m[x,y] = elev("z");
		} else {
			m[x,y] = elev($x);
		}
	}
	y++;
	w = NF;
	h = NR;
}
END {
	l = 1;
	Q[l] = S;
	N[l] = 0;
	for (i = 1; Q[i]; ++i) {
		if (Q[i] == E) break;
		split(Q[i], a, ",");
		x = a[1];
		y = a[2];
		n = N[i];
		if (x > 1 && !V[x-1,y] && m[x-1,y] <= m[x,y]+1) {
			V[x-1,y] = 1;
			Q[++l] = x-1 "," y;
			N[l] = n+1;
		}
		if (x < w && !V[x+1,y] && m[x+1,y] <= m[x,y]+1) {
			V[x+1,y] = 1;
			Q[++l] = x+1 "," y;
			N[l] = n+1;
		}
		if (y > 1 && !V[x,y-1] && m[x,y-1] <= m[x,y]+1) {
			V[x,y-1] = 1;
			Q[++l] = x "," y-1;
			N[l] = n+1;
		}
		if (y < h && !V[x,y+1] && m[x,y+1] <= m[x,y]+1) {
			V[x,y+1] = 1;
			Q[++l] = x "," y+1;
			N[l] = n+1;
		}
		delete Q[i];
		delete N[i];
	}
	print N[i];
}