You are trying to estimate the population of Tasmanian devils using the Capture-Mark-Recapture method. After initially setting your traps, you capture and mark 15 Tasmanian devils. The next night, you re-set your traps and capture 12 Tasmanian devils. Of those that you caught the second night, 7 of them had the mark you gave them the first night. Entering only a whole number as your answer, what is the estimate for your population, given the equation: