> #include<stdio.h>
> #include<stdlib.h>
> #include<string.h>
> 
> const int maxn = 50005;
> int w[maxn], v[maxn],dp[maxn];//w[i]  每种硬币质量   v[i]每种硬币的价值
> #define min(a,b) ((a)<(b)?(a):(b))
> int main()
> {
> 	int t, E, F,n;//E 空罐的质量  F  满罐的质量   1<=E<=F<=10000g  n几种硬币  1<=n<=500
> 	scanf("%d", &t);
> 	getchar();
> 	while (t--)
> 	{
> 		scanf("%d%d", &E, &F);
> 		scanf("%d", &n);
> 		memset(dp, 0x3f, sizeof(dp));
> 		dp[0] = 0;
> 		for (int i = 1; i <= n; i++)
> 		{
> 			scanf("%d%d", v + i,w + i);
> 		}
> 
> 		for (int i = 1; i <= n; i++)
> 		{
> 			for (int j = w[i]; j <= F-E; j++)
> 			{
> 				dp[j] = min(dp[j], dp[j - w[i]] + v[i]);
> 			}
> 		}
> 
> 		if (dp[F - E] != dp[50001])
> 		{
> 			printf("The minimum amount of money in the piggy-bank is %d.\n", dp[F - E]);
> 		}
> 		else
> 		{
> 			printf("This is impossible.\n");
> 		}
> 	}
> 
> 	return 0;
> }