2017 多校训练第一场 KazaQ's Socks

#include
#define test TEST
using namespace std;
typedef long long ll;
const int maxn=100005;
const int mod=1e9+7;

int main(int argc, char const *argv[])
{
ll n,k,cas=1;
while(~scanf("%lld %lld",&n,&k)){
printf("Case #%lld: ",cas++);
if(k<=n){
printf("%lld\n",k);
}
else{
ll T;
k-=n;
T=2*(n-1);
ll m=k%T;
ll temp=n-1;
if(m==0){
printf("%lld\n",n);
}
else if(m==temp){
printf("%lld\n",n-1);
}
else {
printf("%lld\n",m%temp);
}
}
}
return 0;
}