isok = true
for i = 1, 2 do
    s = io.read()
    n = string.len(s)
    if(n <= 5) then
        if(s ~= "0") then
            for j = 1, n do
                ss = string.sub(s, j, j)
                if(j == 1) then
                    if(string.match(ss, "[1-9]") == nil) then
                        isok = false
                    end
                else
                    if(string.match(ss, "[0-9]") == nil) then
                        isok = false
                    end
                end
            end
            if(isok) then
                snum = tonumber(s)
                if(12345 < snum) then isok = false end
            end
        end
    else
        isok = false
    end
end
if(isok) then print("OK") else print("NG") end