严防输出超限（m==0）

#include<stdio.h>
int main()
{
	int m, n, t,p,q;
	
	while (scanf_s("%d", &m) != EOF)
	{
		if (m == 0)
			break;
		int a[1000] = { 0 };
		int sum = 0, j = 0;
		scanf_s("%d", &n);
		

			for (t = 0; t <= n-1; t++)
			{
				scanf_s("%d", &a[t]);
					
			}

			for (j = 0; j <= n-1; j++)
			{
				for (q = 1; q <= n - j-1; q++)
				{
					if (a[j] <= a[j + q])
					{
						p = a[j];
						a[j] = a[j + q];
						a[j + q] = p;
					}
					else
						continue;

				}
			}
			for (j = 0; j <= n-1; j++)
			{
				sum += a[j];
				if (sum >= m)
				{
					printf("%d\n", j+1);
					break;
				}
				else
					continue;

			}
			if (sum < m)
				printf("impossible\n");

			
		
		
	}
	return 0;
}