==5489== 64 errors in context 16 of 16:
==5489== Invalid read of size 8
==5489==    at 0x401679: Matrix<int>::operator*(Matrix<int> const&) const (matrix.hpp:126)
==5489==    by 0x400DB3: main (driver.cpp:16)
==5489==  Address 0x5a1c040 is 0 bytes inside a block of size 32 free'd
==5489==    at 0x4C2C83C: operator delete[](void*) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==5489==    by 0x401090: Matrix<int>::~Matrix() (matrix.hpp:40)
==5489==    by 0x400CBF: main (driver.cpp:12)