Tetrahedron A B C D has A D=B C=28, A C=B D=44, and A B=C D= 52. For any point X in space, define f(X)=A X+B X+C X+D X. The least possible value of f(X) can be expressed as m \sqrt{n}, where m and n are positive integers, and n is not divisible by the square of any prime. Find m+n.