public static void func(int req, int n, int[]pi, Rojok rj, Integer I, Matrix A){
        for(int i=1; i<=n-req+1; i++){
            pi[req] = rj.geti(i);
            func(req+1, n , pi, rj, I,  A);
            rj.pop(i);

            if(req == n) add(pi,I,A);
        }
    }