sprintf(filename1, "C:\\Users\\nikos\\Desktop\\buffers\\tmp_buffer_%d_%d.bin", round, i);
            sprintf(filename2, "C:\\Users\\nikos\\Desktop\\buffers\\tmp_buffer_%d_%d.bin", round, i + 1);
            sprintf(merged_filename, "C:\\Users\\nikos\\Desktop\\buffers\\tmp_buffer_%d_%d.bin", round + 1, i / 2);