#include <stdio.h>

int main()
{
	int N;
	long long S;
	scanf("%d %lld", &N, &S);
	
	int i, k = 0, ans[200001];
	for (i = N; S > 0; i--) {
		if (i <= S) {
			S -= i;
			ans[k++] = i;
		}
	}
	printf("%d\n", k);
	for (i = k - 1; i >= 0; i--) printf("%d ", ans[i]);
	printf("\n");
	fflush(stdout);
	return 0;
}