/*
* 三分查找
*/
#include<cstdio>
#include<cmath>
#define eps 1e-6
//typedef __int64 LL;
int n;
double x[50005], w[50005];
double func(double y){
double res=0;
for(int i=0;i<n;i++){
double a=y-x[i];
a=a<0?-a:a;
res+=a*a*a*w[i];
}
return res;
}
int main(){
int T;
scanf("%d",&T);
for(int t=1;t<=T;t++){
scanf("%d",&n);
for(int i=0;i<n;i++){
scanf("%lf%lf",&x[i],&w[i]);
}
double l=x[0],r=x[n-1],mid,mmid;
while(r-l>eps){
mid=(l+r)/2.0;
mmid=(mid+r)/2.0;
if(func(mid)-func(mmid)>eps){
l=mid;
}
else{
r=mmid;
}
}
printf("Case #%d: %lld ",t,(long long)(func(r)+0.5));
//hdu要用int64
}
}