solve;
printf "The knapsack contains:\n";
printf {(i,s,p) in I: x[i] == 1} " %i", i;

printf("\n");

printf(sum{ i in 1..N}(A[i]*x[i]));

printf(4*PI * sum{ i in 1..N} (A[i]*x[i]) /
	(
		2* sum{i in 1..N-1, j in i+1..N}
			(P[i]*P[j]* y[i,j])									# i < j
		+ sum{i in 1..N}
			(P[i]*P[i]* x[i])									# i = j

		-4 * sum{i in 1..N-2, j in i+1..N-1, k in j+1..N}
			(P[i]*S[j,k]* w[i,j,k])								# j< k --> i < j < k
		-4 * sum{i in 1..N-1, j in i+1..N}
			(P[i]*S[i,j]* y[i,j]) 								# j< k --> i = j < k
		-4 * sum{i in 1..N-2, j in i+1..N-1, k in j+1..N}
			(P[j]*S[i,k]* w[i,j,k]) 							# j< k --> j < i --> j < i < k
		-4 * sum{i in 1..N-1, j in i+1..N}
			(P[j]*S[i,j]* y[i,j]) 								# j< k --> j < i --> j < i = k
		-4 * sum{i in 1..N-2, j in i+1..N-1, k in j+1..N}
			(P[k]*S[i,j]* w[i,j,k]) 							# j< k --> j < i --> j < k < i

		+8 * sum{i in 1..N-3, j in i+1..N-2, k in j+1..N-1, l in k+1..N}
			(S[i,k]*S[j,l]*z[i,j,k,l])							# i < k < j < l

		+8 * sum{i in 1..N-2, j in i+1..N-1, k in j+1..N}
			(S[i,k]*S[j,k]*w[i,j,k])							# i < k < j = l

		+8 * sum{i in 1..N-3, j in i+1..N-2, k in j+1..N-1, l in k+1..N}
			(S[i,l]*S[j,k]*z[i,j,k,l])							# i < k < l < j

		+8 * sum{i in 1..N-2, j in i+1..N-1, k in j+1..N}
			(S[i,j]*S[j,k]*w[i,j,k])							# i < k = j < l

		+8 * sum{i in 1..N-3, j in i+1..N-2, k in j+1..N-1, l in k+1..N}
			(S[i,j]*S[k,l]*z[i,j,k,l])							# i < j < k < l

		+8 * sum{i in 1..N-2, j in i+1..N-1, k in j+1..N}
			(S[i,j]*S[i,k]*w[i,j,k])							# i = k < j < l

		+4 * sum{i in 1..N-1, j in i+1..N}
			(S[i,j]*S[i,j]*y[i,j])								# i = k < j = l
	);)