#include<stdio.h> int main() { int t,n,i,min=10000000000,k; scanf("%d",&t); while(t--) { min=10000000000; scanf("%d%d",&n,&k); int a[n]; for(i=0;i<n;i++) { scanf("%d",&a[i]); if(a[i]<min) min=a[i]; } //printf("%d ",min); if(min>=k) printf("0\n"); else printf("%d\n",k-min); } return 0;

}