text: #include<iostream>
  #include<cstdio>
  #include<cstring>
  #include<algorithm>
  #include<vector>
  #include<queue>
  #include<map>
  #include<set>
  #include<ctime>
  #include<cstdlib>
  #define pb push_back
  #define mp make_pair
  #define fi first
  #define se second
  #define cls(a) memset(a,0,sizeof(a))
  #define rep(i,x,y) for(int i=(x);i<=(y);++i)
  #define per(i,x,y) for(int i=(x);i>=(y);--i)
  using namespace std;
  class StepsConstruct {
  public:
  	string construct(vector <string> board, int k) {
  		
  	}
  };
  