Python-сообщество

 a=[int(i) for i in input().split()]
k=len(a)
b=[]
b.append(a)
for j in range(k-1):
    a=[int(i) for i in input().split()]
    b.append(a)
s = [[0,0,0],[0,0,0],[0,0,0]]
for i in range(k):
    for j in range(k):
        for t in range(k):
            if t!=j:
                s[i][j]+=b[i][t]
            if t!=i:
                s[i][j]+=b[t][j]
print(s)

 s = [[0,0,0],[0,0,0],[0,0,0]]

  s=[[0]*k]*k

  
>>> lst = [[0] * 3 for _ in range(4)]
>>> lst
[[0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0]]
>>> lst[0][0] = 1
>>> lst
[[1, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0]]
>>>