fun Z () = 0;
fun S n = n+1;

fun pr_1_1 x:int = x;

fun pr_1_2 (x:int,y:int) = x;
fun pr_2_2 (x:int,y:int) = y;

fun pr_1_3  (x:int, y:int, z:int) = x;
fun pr_2_3  (x:int, y:int, z:int) = y;
fun pr_3_3  (x:int, y:int, z:int) = z;

fun compose_1 (g1,h)  x = h (g1 x);
fun compose_2 (g1,g2,h)  x = h (g1 x) (g2 x );
fun compose_3 (g1,g2,g3,h)  x = h (g1 x) ( g2 x) (g3 x);

fun pr_rek_1 (g,h) y = 
	if (y=0) 	then g () 
			else h (y-1,pr_rek_1 (g,h)  (y-1) );

fun pr_rek_2 (g,h) x1 y = 
	if (y=0) 	then g x1
			else h (x1,y-1,pr_rek_2 (g,h) x1 (y-1) );

fun pr_rek_3 g h x1 x2 y  = 
	if (y=0)	then g x1 x2  
			else h x1 x2 (y-1) (pr_rek_3 g h  x1 x2 (y-1) );

val c_1_0 = compose_1 (Z,S);
val c_2_0 = compose_1 (c_1_0,S);
val c_3_0 = compose_1 (c_2_0,S);

val c_0_1 = pr_rek_1 (Z, pr_2_2);
val c_1_1 = pr_rek_1 (c_1_0, pr_2_2);
val c_2_1 = pr_rek_1 (c_2_0, pr_2_2);
val c_3_1 = pr_rek_1 (c_3_0, pr_2_2);

val c_0_2 = compose_1 (pr_1_2,c_0_1);
val c_1_2 = compose_1 (pr_1_2,c_1_1);
val c_2_2 = compose_1 (pr_1_2,c_2_1);
val c_3_2 = compose_1 (pr_1_2,c_2_1);

val add = pr_rek_2 (pr_1_1,compose_1 (pr_3_3,S));
val add = function (x,y) -> x+y;

val mult = pr_rek_2 (c_0_1,compose_2 (pr_1_3,pr_3_3,add));