dynamic matrix in python

1# A basic code for matrix input from user 
2  
3R = int(input("Enter the number of rows:")) 
4C = int(input("Enter the number of columns:")) 
5  
6# Initialize matrix 
7matrix = [] 
8print("Enter the entries rowwise:") 
9  
10# For user input 
11for i in range(R):          # A for loop for row entries 
12    a =[] 
13    for j in range(C):      # A for loop for column entries 
14         a.append(int(input())) 
15    matrix.append(a) 
16  
17# For printing the matrix 
18for i in range(R): 
19    for j in range(C): 
20        print(matrix[i][j], end = " ") 
21    print() 

1If you want to take n lines of input where each line contains m space separated integers like:
2
31 2 3
44 5 6 
57 8 9 
6
7a=[] // declaration 
8for i in range(0,n):   //where n is the no. of lines you want 
9 a.append([int(j) for j in input().split()])  // for taking m space separated integers as input

12
2235
33 4 5
4