import sys
from collections import deque

class point:
    def __init__(self, x, y):
        self.x = x
        self.y = y
    def isvalid(self, n, m):
        if self.x >= 0 and self.x < n and self.y>=0 and self.y<m:
            return True
        return False
    def __eq__(self, pnt):
        if self.x == pnt.x and self.y==pnt.y:
            return True
        return False

def valid_points(pnt, n, m):
    rv = []
    for i in [ [-1, 0], [1, 0], [0, 1], [0, -1]]:
        pt = point(pnt.x + i[0], pnt.y + i[1])
        if pt.isvalid(n, m):
            rv.append(pt)

def dfs_util(dp, graph, n, m, G, pnt):
    if G ==pnt:
        return 1
    for pt in valid_points(pnt, n, m):
        adder = 1
        if graph[pt.x][pt.y] == '#':
            adder = graph[pnt.x][pnt.y][1]
        dp[pt.x][pt.y][0] = min(dp[pt.x][pt.y][0], dp[pnt.x][pnt.y][0] + adder)
        dp[pt.x][pt.y][1] = dp[pnt.x][pnt.y][1] + int(graph[pt.x][pt.y] == '#')


def solve(n, m, graph):
    dp = [ [[(n*m)**2, 0] for j in range(m)] for i in range(n) ]
    S = point(-1, -1)
    found = False
    for i in range(n):
        for j in range(m):
            if graph[i][j] =='S':
                S = point(i, j)
                found=True
                break
        if found:
            break

    G = point(-1, -1)
    found = False
    for i in range(n):
        for j in range(m):
            if graph[i][j] =='G':
                G = point(i, j)
                found=True
                break
        if found:
            break

    dp[S.x][S.y] = 0

    dfs_util(dp, graph, n, m, G, S)

    return dp[G.x][G.y]



def main(lines):
    # このコードは標準入力と標準出力を用いたサンプルコードです。
    # このコードは好きなように編集・削除してもらって構いません。
    # ---
    # This is a sample code to use stdin and stdout.
    # Edit and remove this code as you like.

    n, m = map(int, lines[0].strip().split(' '))
    graph = lines[1:n+1]
    print(solve(n, m, graph))


if __name__ == '__main__':
    lines = []
    for l in sys.stdin:
        lines.append(l.rstrip('\r\n'))
    main(lines)