3r3r3r3r

def printMatrix ( matrix ):
   for i in range ( len(matrix) ):
      for j in range ( len(matrix[i]) ):
          print ( "{:4d}".format(matrix[i][j]), end = "" )
      print ()


n,m = 5,7
l = [[0]*n for x in range(m)]
k = 0
num = 1
while num < n*m:
    for j in range(k,n-k):
        l[k][j] = num
        num += 1


    for j in range(k+1,m-k):
        l[j][n-k-1] = num
        num += 1


    for j in range(n-k-2,k,-1):
        l[m-k-1][j] = num
        num += 1

    for j in range(m-k-1,k,-1):
        l[j][k] = num
        num +=1
    k+=1


printMatrix(l)