begin 

    comment library 1;

    integer 
        x,
        n,
        k;
    real procedure sigma(i, k, l, t);
        value 
            l;
        integer 
            i,
            k,
            l;
        real 
            t;
        begin 
        real 
            x;
        x := 0;
        for i := k step 1 until l do 
            x := t + x;
        sigma := x
        end sigma;

    x := sigma(n, 1, 4, sigma(k, 1, n, 2) - 1);

    comment   working in august 1960 at amsterdam;

    outreal(1, x)
end