# for i in $(seq 1 5); do time ./matrix_mult_18.o; done
       61.59 real        59.84 user         0.81 sys
       61.70 real        59.81 user         0.94 sys
       62.24 real        60.44 user         0.84 sys
       61.64 real        59.73 user         0.96 sys
       61.72 real        60.00 user         0.77 sys