#include <iostream>
#include <stdio.h>
using namespace std;

int trace[2016][2016];

int MAX(int a, int b){
	return a>b ? a : b;
}

int main() {
	while(1){
		int M, L;
		scanf("%d%d", &M, &L);
		if(M == 0 && L == 0) return M+L;
		int N;
		scanf("%d", &N);
		int boxes[2016];
		int sum = 0;
		for(int i = 1; i <= N; i++){
			scanf("%d", boxes+i);
			sum += *(boxes+i);
		}
		if(sum > M+L){
			printf("Impossible to distribute\n");
			continue;
		}
		int lower = sum - L, upper = M;
		trace[0][0] = 0;
		for(int i = 1; i <= upper; i++){
			trace[0][i] = -1;
		}
		for(int i = 1; i <= N; i++){
			for(int j = 0; j <= upper; j++){
				if(j < boxes[i]){
					if(trace[i-1][j] != -1) trace[i][j] = 0;
					else trace[i][j] = -1;
				}
				else{
					if(trace[i-1][j] != -1) trace[i][j] = 0;
					else if(trace[i-1][j-boxes[i]] != -1) trace[i][j] = 1;
					else trace[i][j] = -1;
				}
				if(trace[i][j] != -1 && j >= lower){
					int temp[2004];
					int tempNum = 0;
					int k = i;
					int l = j;
					while(k > 0){
						if(trace[k][l] == 1){
							temp[tempNum] = k;
							tempNum ++;
							l -= boxes[k];
						}
						k --;
					}
					printf("%d ", tempNum);
					for(int s = tempNum - 1; s >= 0; s--){
						printf("%d ", temp[s]);
					}
					printf("\n");
					goto done;
				}
			}
		}
		printf("Impossible to distribute\n");
		done:
				continue;
	}
}