#include <iostream>

using namespace std;

void nhap(int &x, char name) {
	do {
		cout<<"Nhap "<<name<<": "; cin>>x;
		if (x < 1 || x > 20) cout<<"\nNhap 1 <= "<<name<<" <= 20";
	} while (x < 1 || x > 20);
}

void nhap_ma_tran(int a[][20], int m, int n, char name) {
	for (int i = 0; i < m; i++) {
		for (int j = 0; j < n; j++) {
			cout<<name<<"["<<i<<","<<j<<"] = "; cin>>a[i][j];
		}
	}
}

void hien_thi(int a[][20], int m, int n) {
	for (int i = 0; i < m; i++) {
		for (int j = 0; j < n; j++) {
			cout<<"\t"<<a[i][j];
		}
		cout<<endl;
	}
}

void tong_ma_tran(int a[][20], int b[][20], int c[][20], int m, int n, int p, int q) {
	if (m == q && n == p) {
		for (int i = 0; i < m; i++) {
			for (int j = 0; j < n; j++) {
				c[i][j] = a[i][j] + b[i][j];
			}
		}
		cout<<"Tong ma tran C = A + B la: "<<endl;
		hien_thi(c,m,n);
	} else {
		cout<<"\nKhong the tinh tong 2 ma tran khong cung kich thuoc"<<endl;
	}
}

void tich_ma_tran(int a[][20], int b[][20], int d[][20], int m, int n, int p, int q) {
	if (n == p) {
		for (int i = 0; i < m; i++)
			for (int j = 0; j < p; j++) {
				d[i][j] = 0;
				for (int k = 0; k < n; k++)
					d[i][j] += a[i][k] * b[k][j];
			}
		cout<<"Tich ma tran D = A * B la: "<<endl;
		hien_thi(d,m,q);
	} else {
		cout<<"\nKhong the tinh tich 2 ma tran khong cung kich thuoc"<<endl;
	}
}

int main() {
	int m,n,p,q;
	int a[20][20], b[20][20], c[20][20], d[20][20];
	nhap(m,'m');
	nhap(n,'n');
	nhap(p,'p');
	nhap(q,'q');
	nhap_ma_tran(a,m,n,'a');
	nhap_ma_tran(b,p,q,'b');
	tong_ma_tran(a,b,c,m,n,p,q);
	tich_ma_tran(a,b,d,m,n,p,q);
	return 0;
}