http://tjuacm.chaosheng.top/problem.php?id=1251

#include <iostream>
#include <cstdio>
#include <cstring>
#include <queue>

using namespace std;

int main(){
    int t, n, k;
    cin >> t;
    for(int j = 1; j <= t; j++){
        cin >> n >> k;
        queue<int> q;
        for(int i = 1; i <= n; i++){
            q.push(i);
        }

        int tt = 1;
        while(q.size() > 1) {
            if(tt % k == 0){
                q.pop();
            }else{
                int tmp = q.front();
                q.pop();
                q.push(tmp);
            }
            tt++;
        }
        printf("Case %d: %d\n", j, q.front());
    }
    return 0;
}