print((function (f)
	local a,b,c = f(),f(),f()
	if a>c then return c end
	local d = a+b-1
	return tostring(c/d*a+(c%d<a and c%d or a)):sub(1,-3)
end)((function (M)
	M.cdef 'int scanf(const char *, ...);'
	local C,c = M.C,M.new("long[1]")
	return function () C.scanf("%ld",c) return c[0] end
end)(require'ffi')))