#include <iostream.h>
#include <fstream.h>

main(int argc, char *argv[]) {
	//definition of the variables.
	int mtx1[20][20], mtx2[20][20], mtx3[20][20];
	int n, i, j, k;

	//exit if the number of arguments is not 2.
	if(argc != 3) {
		cerr << "Usage: mm <filename1> <filename2>\n";
		return 1;
	}

	//open the input file 1. exit if an error occurs.
	ifstream fin1(argv[1]);
	if(!fin1) {
		cerr << "Can't open file1!\n";
		return 1;
	}

	//read the input file 1.
	fin1 >> n;				//read the number of rows and columns.
	for(j=1; j<=n; j++) {
		for(i=1; i<=n; i++) {
			fin1 >> mtx1[i][j];	//read the elements of the matrix.
		}
	}
	fin1.close();				//close the file 1.

	//open the input file 2. exit if an error occurs.
	ifstream fin2(argv[2]);
	if(!fin2) {
		cerr << "Can't open file2!\n";
		return 1;
	}

	fin2 >> n;				//read the number of rows and columns.
	for(j=1; j<=n; j++) {
		for(i=1; i<=n; i++) {
			fin2 >> mtx2[i][j];	//read the elements of the matrix.
		}
	}
	fin2.close();				//close the file 2.

	//fill the matrix 3 for the result with zero.
	for(j=1; j<=n; j++) {
		for(i=1; i<=n; i++) {
			mtx3[i][j] = 0;
		}
	}

	//multiply the matrices.
	for(j=1; j<=n; j++) {
		for(i=1; i<=n; i++) {
			for(k=1; k<=n; k++) {
				mtx3[i][j] += mtx2[i][k] * mtx1[k][j];
			}
		}
	}

	//output the result.
	cout << n << "\n";
	for(j=1; j<=n; j++) {
		for(i=1; i<=n; i++) {
			cout << mtx3[i][j];
			if(i < n) {
				cout << "\t";
			}
		}
	cout << "\n";
	}

	return 0;
}					//end of the program.