Define a function f mapping positive integers to positive integers by f(1)=1, and f(n)=f(n-1)+n if f(n-1)<=n and f(n)=f(n-1)-n if f(n-1)>n

For n≥2,
i) Find the smallest integer n such that f(n) = 1,000,000
ii) Find the smallest integer n such that f(n) = 2,000,000