A,B,T = gets.chomp.split(" ").map(&:to_i)
ans = 0
baisuu = []
for i in 1..20 do
    baisuu[i] = A * i
end
for i in 1..T do 
    if baisuu.any? {|w| w == i }
        ans = ans + B
    end
end

puts ans