If the minimum positive period of function f (x) = cos (Wx + 3 / π) (W > 0) is t, t ∈ (1,3), what is the maximum value of positive integer w

If the minimum positive period of function f (x) = cos (Wx + 3 / π) (W > 0) is t, t ∈ (1,3), what is the maximum value of positive integer w

Because t = w / 2 π, and t ∈ (1,3), so 2 π / 3 < w < 2 π, and W is a positive integer, so w = π