row ,col = list( map(int,input().split() ) ) #row行,col列 a = [ list( map(int,input().split() ) ) for x in range(row) ] res =0 #处理数据 for i in range(row): #i行索引 for j in range(col):#j列表的索引 if i==0 or i == row-1 or j==0 or j == col-1: res = res + a[i][j] print(res)