Sam's portfolio has two securities. The Pfizer stock has an expected return of 17% and a standard deviation of 24%. The Moderna stock has an expected return of 10% and a standard deviation of 24%. If the correlation between Pfizer and Moderna stocks is -1, what is the lowest possible standard deviation that Sam's portfolio can have? Answer in percentage points and include four decimal places; do not include the '% your answer, e.g., 10.1234 would be entered if the answer was 10.1234%. You do ot need to input trailing zeros. ur