arr = []
arr.append([1,2])
arr.append([3,4,5,6])
arr.append([7,8,9])
print(arr)
for i in range(len(arr)):
for j in range(len(arr[i])):
print(arr[i][j])
YXJyID0gW10KYXJyLmFwcGVuZChbMSwyXSkKYXJyLmFwcGVuZChbMyw0LDUsNl0pCmFyci5hcHBlbmQoWzcsOCw5XSkKcHJpbnQoYXJyKQpmb3IgaSBpbiByYW5nZShsZW4oYXJyKSk6CiAgICBmb3IgaiBpbiByYW5nZShsZW4oYXJyW2ldKSk6CiAgICAgICAgcHJpbnQoYXJyW2ldW2pdKQo=