local function query(i)
    print(i)
    io.flush()
    local a = io.read()
    if a == 'Vacant' then
        os.exit()
    else
        return a:sub(1,1)
    end
end

local function available(a, s_a, b, s_b)
    if a % 2 == b % 2 then
        return s_a ~= s_b
    else
        return s_a == s_b
    end
end

local N = io.read("n","l")
local left = 0
local right = N - 1
local s_left = query(left)
local s_right = query(right)
while true do
    local mid = (left + right) // 2
    local s_mid = query(mid)
    if available(left, s_left, mid, s_mid) then
        right = mid
        s_right = s_mid
    else
        left = mid
        s_left = s_mid
    end
end
