Two research submarines start to rise vertically toward the ocean surface. The Tri-I sub is at 4,863 feet below sea level (or -4,863 feet) and is ascending 81.1 per minute. The Quad-II sub is at 3,645 feet below sea level (or -3,645 feet) and is ascending 76.9 feet per minute. If the ocean surface is at 0 feet, how many minutes (m) must elapse for the two submarines to reach the same depth?