C++ :

#include <iostream>
#include <cstdio>
#define Maxn 1009
#include <cctype>
#include <cstring>
using namespace std;
int  a[Maxn][Maxn],b[Maxn][Maxn],c[Maxn][Maxn];
int main()
{   int m,n,r;
    scanf("%d%d%d",&m,&n,&r);
    for(int i=1;i<=m;i++){
        for(int j=1;j<=n;j++){
            scanf("%d",&a[i][j]);
        }
    }
    for(int i=1;i<=n;i++){
        for(int j=1;j<=r;j++){
            scanf("%d",&b[i][j]);
        }
    }
    printf("%d %d\n",m,r);
    for(int i=1;i<=m;i++){
        for(int j=1;j<=r;j++){
            int y=0;
            for(int k=1;k<=n;k++){
                int x=0;
                x=a[i][k]*b[k][j];
                y+=x;
            }


            c[i][j]=y;
            printf("%d ",c[i][j]);
        }
    printf("\n");
    }
    return 0;
}

python: m,n,r=map(int,input().split())

A=[[0 for a1 in range(n)] for a2 in range(m)]

B=[[0 for b1 in range(n)] for b2 in range(r)]

gp=[]

hp=[]

g=[]

h=[]

for a3 in range(m):

g1=input().split()

if len(g1)==n:

gp+=g1

for b3 in range(n):

h1=input().split()

if len(h1)==r:

hp+=h1

for a4 in gp:

g.append(int(a4))

for b4 in hp:

h.append(int(b4))

for k in range(len(g)):

A[k//n][k%n]=g[k]

for j in range(len(h)):

B[j%r][j//r]=h[j]

def v(x,y):

z=len(x)

v=0

for im in range(z):

t=x[im]*y[im]

v+=t

return v

AB=[[0 for c1 in range(r)] for c2 in range(m)]

for i in range(m):

for l in range(r):

AB[i][l]=v(A[i],B[l])

print(m,r)

p=''

for e in range(len(AB)):

for f in AB[e]:

p+=str(f)+' '

print(p)

p=''