a,b,c,d are distinct pairwise co-prime +ve integers with a^2 + b^2 = c^2 + d^2, lowest possible value of a + b + c + d?

Question

If a, b, c and d are distinct pairwise co-prime positive integers such that a^2 + b^2 = c^2 + d^2, find the lowest possible value of a + b + c + d?