#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <limits.h>
#define ARRSIZ 32
// komentar 2024-05-13: testi iz ucilnica2223 passajo, toda sem prepozen za oddajo
struct množica {
	int n;
	int arr[ARRSIZ];
};
void najdi_targete (struct množica ** shramba, int * shramba_len, int * shramba_sizeof, int n, int * t, int * stack, int globina, int target) {
	if (target < 0)
		return;
	if (!target) {
		if (*shramba_len >= *shramba_sizeof)
			*shramba = realloc(*shramba, (*shramba_sizeof *= 2)*sizeof(struct množica));
		memcpy((*shramba)[*shramba_len].arr, stack, sizeof(int)*globina);
		(*shramba)[(*shramba_len)++].n = globina;
		return;
	}
	for (int i = globina == 0 ? 0 : stack[globina-1]+1; i < n; i++) {
		stack[globina] = i;
		najdi_targete(shramba, shramba_len, shramba_sizeof, n, t, stack, globina+1, target-t[i]);
	}
}
void najdi_množice (struct množica * shramba, int shramba_len, int * stack, int * t, bool * used, int n, int globina, int k) {
	if (globina == k) {
		for (int i = 0; i < n; i++)
			if (!used[i])
				return;
		printf("{");
		for (int i = 0; i < k; i++) {
			printf("{");
			int donefirst = false;
			for (int j = 0; j < shramba[stack[i]].n; j++) {
				printf("%s%d", donefirst ? ", " : "", t[shramba[stack[i]].arr[j]]);
				donefirst = true;
			}
			printf("}");
			if (i != k-1)
				printf(", ");
		}
		printf("}\n");
		return;
	}
	for (int i = globina == 0 ? 0 : stack[globina-1]+1; i < shramba_len; i++) {
		bool contpls = false;
		for (int j = 0; j < shramba[i].n; j++)
			if (used[shramba[i].arr[j]]) {
				contpls = true;
				break;
			}
		if (contpls)
			continue;
		for (int j = 0; j < shramba[i].n; j++)
			used[shramba[i].arr[j]] = true;
		stack[globina] = i;
		najdi_množice(shramba, shramba_len, stack, t, used, n, globina+1, k);
		for (int j = 0; j < shramba[i].n; j++)
			used[shramba[i].arr[j]] = false;
	}
}
int compar (const void * a, const void * b) {
	struct množica * c = ((struct množica *) a);
	struct množica * d = ((struct množica *) b);
	int e = INT_MAX;
	int f = INT_MAX;
	for (int i = 0; i < c->n; i++) {
		if (c->arr[i] < e)
			e = c->arr[i];
	}
	for (int i = 0; i < d->n; i++) {
		if (d->arr[i] < f)
			f = d->arr[i];
	}
	if (e == f)
		return 0;
	return e > f ? 1 : -1;
}
int main (void) {
	int n, k, sum = 0;
	scanf("%d %d\n", &n, &k);
	int t[n];
	for (int i = 0; i < n; i++) {
		scanf("%d", &t[i]);
		sum += t[i];
	}
	if (sum % k)
		return 0;
	int shramba_sizeof = 2;
	int shramba_len = 0;
	struct množica * shramba = malloc(sizeof (struct množica) * shramba_sizeof);
	int stack[ARRSIZ];
	najdi_targete(&shramba, &shramba_len, &shramba_sizeof, n, t, stack, 0, sum/k);
	qsort(shramba, shramba_len, sizeof (struct množica), compar);
	for (int i = 0; i < shramba_len; i++) {
		for (int j = 0; j < shramba[i].n; j++) {
			fprintf(stderr, "%d, ", t[shramba[i].arr[j]]);
		}
		fprintf(stderr, "\n");
	}
	bool used[n];
	memset(used, 0, sizeof used);
	najdi_množice(shramba, shramba_len, stack, t, used, n, 0, k);
}