A researcher wants to design an experiment comparing a treatment group to an control group. The researcher is evaluating the effect of a new drug on systolic blood pressure (SBP). The researcher estimates the standard deviation of SBP in the population to be 10 mmHg. The drug is estimated to decrease SBP by 5 mmHg on average. What is the total sample size required to detect this effect with 90% power? Assume SBP is approximately normally distributed in the population.