produceTime,produceNum,finishTime=gets.split.map(&:to_i)
finishTime += 0.5
biscuitNum = 0
# p produceTime
# p produceNum
# p finishTime
nextTime = produceTime
N = 20
N.times do |i|
    # p "i+1:" + (i+1).to_s
    if i+1 >= finishTime
        puts biscuitNum
        break
    end
    if i+1 == nextTime
        biscuitNum += produceNum
        # p "biscuitNum: " + biscuitNum.to_s
        nextTime += produceTime
        # p "nextTime: " + nextTime.to_s
    end
end