#include<bits/stdc++.h>

#define LL long long

#define LD long double

#define ull unsigned long long

#define fi first

#define se second

#define mk make_pair

#define PLL pair<LL, LL>

#define PLI pair<LL, int>

#define PII pair<int, int>

#define SZ(x) ((int)x.size())

#define ALL(x) (x).begin(), (x).end()

using namespace std;

const int N = 1e6 + ;

const int inf = 0x3f3f3f3f;

const LL INF = 0x3f3f3f3f3f3f3f3f;

const int mod = 1e6 + ;

const int p = 1e6 + ;

const double eps = 1e-;

const double PI = acos(-);

template<class T, class S> inline void add(T& a, S b) {a += b; if(a >= mod) a -= mod;}

template<class T, class S> inline void sub(T& a, S b) {a -= b; if(a < ) a += mod;}

template<class T, class S> inline bool chkmax(T& a, S b) {return a < b ? a = b, true : false;}

template<class T, class S> inline bool chkmin(T& a, S b) {return a > b ? a = b, true : false;}

int n, m;

int G[][];

int vtomask[][ << ];

int dp[ << ], pre[ << ][];

vector<int> road[ << ][][];

vector<PII> ans;

int main() {

    memset(dp, inf, sizeof(dp));

    scanf("%d%d", &n, &m);

    for(int i = ; i < m; i++) {

        int u, v; scanf("%d%d", &u, &v);

        u--; v--;

        G[u][v] = G[v][u] = ;

    }

    for(int i = ; i < n; i++) {

        for(int mask = ; mask < ( << n); mask++) {

            for(int j = ; j < n; j++) {

                if(mask >> j & ) {

                    if(G[i][j]) vtomask[i][mask]++;

                }

            }

        }

    }

    for(int i = ; i < n; i++) road[ << i][i][i].push_back(i);

    for(int mask = ; mask < ( << n); mask++) {

        for(int u = ; u < n; u++) {

            for(int v = ; v < n; v++) {

                if(!SZ(road[mask][u][v])) continue;

                for(int z = ; z < n; z++) {

                    if(mask >> z & ) continue;

                    if(!G[v][z]) continue;

                    int nxtmask = mask | ( << z);

                    if(SZ(road[nxtmask][u][z])) continue;

                    road[nxtmask][u][z] = road[mask][u][v];

                    road[nxtmask][u][z].push_back(z);

                }

            }

        }

    }

    dp[] = ;

    for(int mask = ; mask < ( << n); mask++) {

        if(dp[mask] >= inf) continue;

        for(int u = ; u < n; u++) {

            if(mask >> u & ) continue;

            if(!vtomask[u][mask]) continue;

            if(vtomask[u][mask] >= ) {

                int nxtmask = mask | ( << u);

                if(chkmin(dp[nxtmask], dp[mask] + )) {

                    pre[nxtmask][] = mask;

                    pre[nxtmask][] = u;

                    pre[nxtmask][] = -;

                }

            }

            for(int v = u + ; v < n; v++) {

                if(mask >> v & ) continue;

                if(!vtomask[v][mask]) continue;

                int amask = (( << n) - ) ^ mask ^ ( << u) ^ ( << v);

                for(int smask = amask; ; smask = (smask - ) & amask) {

                    int tmask = smask | ( << u) | ( << v);

                    if(SZ(road[tmask][u][v])) {

                        if(chkmin(dp[mask | tmask], dp[mask] + SZ(road[tmask][u][v]) + )) {

                            pre[mask | tmask][] = mask;

                            pre[mask | tmask][] = u;

                            pre[mask | tmask][] = v;

                        }

                    }

                    if(!smask) break;

                }

            }

        }

    }

    printf("%d\n", dp[( << n) - ]);

    int mask = ( << n) - ;

    while(mask != ) {

        int pmask = pre[mask][];

        int u = pre[mask][];

        int v = pre[mask][];

        if(~v) {

            int tmask = mask ^ pmask;

            for(int i = ; i < SZ(road[tmask][u][v]); i++)

                ans.push_back(mk(road[tmask][u][v][i - ], road[tmask][u][v][i]));

            for(int i = ; i < n; i++) {

                if((pmask >> i & ) && G[u][i]) {

                    ans.push_back(mk(i, u));

                    break;

                }

            }

            for(int i = ; i < n; i++) {

                if((pmask >> i & ) && G[v][i]) {

                    ans.push_back(mk(i, v));

                    break;

                }

            }

        } else {

            for(int i = , c = ; c; i++) {

                if(G[u][i] && (pmask >> i & )) {

                    ans.push_back(mk(u, i));

                    c--;

                }

            }

        }

        mask = pmask;

    }

    for(auto& t : ans) printf("%d %d\n", t.fi + , t.se + );

    return ;

}

/*

*/