#include <iostream>
#include <sstream>
#include <iomanip>
#include <vector>
#include <string>
#include <map>
#include <set>
#include <algorithm>
#include <numeric>
#include <iterator>
#include <functional>
#include <complex>
#include <queue>
#include <stack>
#include <cmath>
#include <cassert>
#include <cstring>
using namespace std;
typedef long long LL;
typedef complex<double> CMP;

class PrefixFreeSuperset { public:
	long long minSumLength(vector <string> cur, long long k) 
	{
		map<int,LL> open; {
			string me("");
			rec(me, cur, open);
		}

		LL totalLen = 0;
		for(int i=0; i<cur.size(); ++i)
			totalLen += cur[i].size();
		k -= cur.size();

		while(k) {
			if( open.empty() )
				return -1;
			map<int,LL>::iterator it = open.begin(); 
			int lll = it->first;
			LL  ccc = it->second;
			open.erase(it);

			if( k <= ccc ) {
				totalLen += lll*k;
				k         = 0;
			}
			else if( k <= ccc + open[lll+1] ) {
				totalLen += lll*ccc;
				k        -= ccc;
			}
			else if( k <= ccc*2 + open[lll+1] ) {
				LL div = k - (ccc+open[lll+1]);
				open[lll+1] += div*2;
				totalLen += (ccc-div)*lll;
				k        -= (ccc-div);
			}
			else
				open[lll+1] += ccc*2;
		}
		return totalLen;
	}

	void rec(string& me, const vector<string>& prefix, map<int,LL>& open)
	{
		bool iamprefix = false;
		for(int i=0; i<prefix.size(); ++i)
			if( me == prefix[i] )
				return;
			else if( is_prefix(me, prefix[i]) )
				iamprefix = true;
		if( iamprefix )
		{
			me += '0';
			rec(me, prefix, open);
			me.resize(me.size()-1);
			me += '1';
			rec(me, prefix, open);
			me.resize(me.size()-1);
		}
		else
		{
			open[me.size()] ++;
		}
	}

	bool is_prefix(const string& s, const string& t)
	{
		return s.size()<=t.size() && s==t.substr(0,s.size());
	}
};

// BEGIN CUT HERE
#include <ctime>
double start_time; string timer()
 { ostringstream os; os << " (" << int((clock()-start_time)/CLOCKS_PER_SEC*1000) << " msec)"; return os.str(); }
template<typename T> ostream& operator<<(ostream& os, const vector<T>& v)
 { os << "{ ";
   for(typename vector<T>::const_iterator it=v.begin(); it!=v.end(); ++it)
   os << '\"' << *it << '\"' << (it+1==v.end() ? "" : ", "); os << " }"; return os; }
void verify_case(const long long& Expected, const long long& Received) {
 bool ok = (Expected == Received);
 if(ok) cerr << "PASSED" << timer() << endl;  else { cerr << "FAILED" << timer() << endl;
 cerr << "\to: \"" << Expected << '\"' << endl << "\tx: \"" << Received << '\"' << endl; } }
#define CASE(N) {cerr << "Test Case #" << N << "..." << flush; start_time=clock();
#define END	 verify_case(_, PrefixFreeSuperset().minSumLength(cur, k));}
int main(){

CASE(0)
	string cur_[] = {"010"};
	  vector <string> cur(cur_, cur_+sizeof(cur_)/sizeof(*cur_)); 
	long long k = 4LL; 
	long long _ = 9LL; 
END
CASE(1)
	string cur_[] = {"01","000"};
	  vector <string> cur(cur_, cur_+sizeof(cur_)/sizeof(*cur_)); 
	long long k = 4LL; 
	long long _ = 9LL; 
END
CASE(2)
	string cur_[] = {"0011","011110101","11101010111","11101010100000000","11101010100000001111"};
	  vector <string> cur(cur_, cur_+sizeof(cur_)/sizeof(*cur_)); 
	long long k = 1000000000000LL; 
	long long _ = 39971901640560LL; 
END
CASE(3)
	string cur_[] = {"010","00","011","1"};
	  vector <string> cur(cur_, cur_+sizeof(cur_)/sizeof(*cur_)); 
	long long k = 4LL; 
	long long _ = 9LL; 
END
CASE(4)
	string cur_[] = {"010","00","011","1"};
	  vector <string> cur(cur_, cur_+sizeof(cur_)/sizeof(*cur_)); 
	long long k = 5LL; 
	long long _ = -1LL; 
END
CASE(5)
	string cur_[] = {"0011010",
"0011011110",
"00110111001",
"0011011111",
"00110111000",
};
	  vector <string> cur(cur_, cur_+sizeof(cur_)/sizeof(*cur_)); 
	long long k = 9LL; 
	long long _ = 58LL; 
END
/*
CASE(6)
	string cur_[] = ;
	  vector <string> cur(cur_, cur_+sizeof(cur_)/sizeof(*cur_)); 
	long long k = LL; 
	long long _ = LL; 
END
*/
}
// END CUT HERE
