# Problem 531: Chinese leftovers
Let g(a,n,b,m) be the smallest non-negative solution x to the system:x =
a mod nx = b mod m if such a solution exists, otherwise 0. E.g.
g(2,4,4,6)=10, but g(3,4,4,6)=0. Let φ(n) be Euler's totient function.
Let f(n,m)=g(φ(n),n,φ(m),m) Find ∑f(n,m) for 1000000 ≤ n < m <
1005000