dattam.cpp

//#include<bits/stdc++.h>
#include<fstream>
#include<vector>
#include<iostream>
#include <climits>

#define long long long
#define nln '\n'

const long N = 45;

using namespace std;

fstream f1, f2;

inline void openf()
{
    f1.open("dattam.inp", ios:: in);
    f2.open("dattam.out", ios:: out);
}

inline void closef()
{
    f1.close();
    f2.close();
}

long m, n;
vector<vector<long>> a(N);

void data()
{
    cin >> n >> m;
    for (long i = 0; i != m; ++i)
    {
        long x, y;
        cin >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
}

vector<bool> cen(N, 0);
long mic = SHRT_MAX;

void build(long i)
{
    if (i > n)
    {
        long ok = 1;
        for (long j = 1; j-1 != n; ++j)
            if (!cen[j])
            {
                long sat = 0;
                for (const auto &u : a[j])
                    if (cen[u])
                    {
                        sat = 1;
                        break;
                    }
                if (!sat)
                {
                    ok = 0;
                    break;
                }
            }
        if (ok)
        {
            long coc = 0;
            for (long i = 1; i-1 != n; ++i)
                if (cen[i])
                    ++coc;
            if (coc < mic)
                mic = coc;
        }
        return;
    }

    bool put = 0;
    if (cen[i])
        put = 1;
    else
    {
        for (const auto &j : a[i])
            if (cen[j])
            {
                put = 1;
                break;
            }
    }
    if (put == 0)
    {
        build(i+1);
        cen[i] = 1;
        build(i+1);
        cen[i] = 0;
    }
    else
        build(i+1);
}

void process()
{
    build(1);
}

void view()
{
    cout << mic << nln;
}

int main()
{
    //cout << "Le Duc Phuc Long" << endl;
    openf();
    data();
    process();
    view();
    closef();
    return 0;
}