#include <stdio.h>
#include <stdlib.h>
struct node
{
int c;
int d;
}nodes[100010];
int cmp(const void * a,const void * b)
{
return (*(node *)a).d-(*(node *)b).d;
}
int main()
{
int t,n,i,k=1;
__int64 max,sum;
scanf("%d",&t);
while(t--)
{
max=0;
sum=0;
scanf("%d",&n);
for(i=0;i<n;i++)
scanf("%d%d",&nodes[i].c,&nodes[i].d);
qsort(nodes,n,sizeof(nodes[0]),cmp);
for(i=0;i<n;i++)
{
sum+=nodes[i].c;
if(sum>nodes[i].d&&max<sum-nodes[i].d)
max=sum-nodes[i].d;
}
printf("Case %d: %I64d\n",k++,max);
}
return 0;
}