#include<cstdio>
#include<iostream>
#include<sstream>
#include<cmath>
#include<cstring>
#include<cstdlib>
#include<cassert>
#include<ctime>
#include<algorithm>
#include<iterator>
#include<iostream>
#include<cctype>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<queue>
#include<list>
using namespace std;




const int N=7;
int done[1<<12],gdo2[1<<12];
const int INF=1000000;
 
int g(int mask,int lvl){
  assert(mask<(1<<N));
 
   printf("MASK=%d\n",mask);
 
	if(gdo2[mask]) return gdo2[mask];
 
	if(lvl==N){
		if(done[mask]) return INF;
		 return mask;
	 }
 	 int ans=INF,i;
	 if(done[mask]==0) ans=mask;
	for(i=0;i<N;i++)
		if((mask&(1<<i))){
			ans=min(ans,min(g(mask^(1<<i) ,lvl+1),g(mask,lvl+1)));
		}
 
	return gdo2[mask]=ans;
  
}
 
int main(){
	    
    	done[0]=done[1]=done[3]=done[2]=done[6]=done[4]=done[5]=done[7]=done[15]=1;
 
	     cout <<g(15,0)<<endl;
 
	return 0;
}