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(99, X)
end