如題，小弟一直很納悶，到底要如何用while迴圈讀入多組測資RRRRRR (崩潰...)

以下是我的python程式碼

import sys
while True:
    a = []
    res = ""
    a = sys.stdin.read().split()
    if len(a):
        row = int(a[0])
        col = int(a[1])
        a.pop(0)
        a.pop(0)
        for i in range(0,col):
            for j in range(i,(i+col*(row-1))+1,col):
                res += a[j] + " "
            res = res[:-1]
            res += "\n"
        print(res)
    else:
        break