uva 12751

#include<bits/stdc++.h>
using namespace std;
int sum[100000];
void solve(int n){
    int sm=0;
    sum[0]=0;
    for(int i=1;i<=n;i++){
        sm+=i;
        sum[i]=sm;
    }
}
int main(){
    solve(100000);
    int tc,n,k,x;
    scanf("%d",&tc);
    for(int j=1;j<=tc;j++){
        scanf("%d %d %d",&n,&k,&x);
        int y=x-1;
        int req=k+y;
        int ans= sum[req]-sum[x-1];
        int fin=sum[n]-ans;
        printf("Case %d: %d\n",j,fin);
    }
    return 0;
}