#include <iostream>
using namespace std;
 
// общий код
template <int N, int M> struct Matrix_ {
	double arr[N][M];
	Matrix_() {
		arr[0][0] = 1;
	}
 
};
 
// Специализация
 
template <int N, int M> struct Matrix : public Matrix_<N, M> {};
 
template<>
struct Matrix<4,4> : public Matrix_<4,4> {
	Matrix& yoba() {
		return (*this);
	}
};
 
int main() {
	// your code goes here
	Matrix<1,2> m1;
	Matrix<4,4> m2;
	m2.yoba();
	return 0;
}

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