#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 + 7;
const int inf = 0x3f3f3f3f;
const LL INF = 0x3f3f3f3f3f3f3f3f;
const int mod = 1e6 + 3;
const int p = 1e6 + 3;
const double eps = 1e-8;
const double PI = acos(-1);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 < 0) 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[14][14];
int vtomask[14][1 << 14];
int dp[1 << 14], pre[1 << 14][3];
vector<int> road[1 << 14][14][14];
vector<PII> ans;int main() {memset(dp, inf, sizeof(dp));scanf("%d%d", &n, &m);for(int i = 0; i < m; i++) {int u, v; scanf("%d%d", &u, &v);u--; v--;G[u][v] = G[v][u] = 1;}for(int i = 0; i < n; i++) {for(int mask = 0; mask < (1 << n); mask++) {for(int j = 0; j < n; j++) {if(mask >> j & 1) {if(G[i][j]) vtomask[i][mask]++;}}}}for(int i = 0; i < n; i++) road[1 << i][i][i].push_back(i);for(int mask = 0; mask < (1 << n); mask++) {for(int u = 0; u < n; u++) {for(int v = 0; v < n; v++) {if(!SZ(road[mask][u][v])) continue;for(int z = 0; z < n; z++) {if(mask >> z & 1) continue;if(!G[v][z]) continue;int nxtmask = mask | (1 << z);if(SZ(road[nxtmask][u][z])) continue;road[nxtmask][u][z] = road[mask][u][v];road[nxtmask][u][z].push_back(z);}}}}dp[1] = 0;for(int mask = 1; mask < (1 << n); mask++) {if(dp[mask] >= inf) continue;for(int u = 0; u < n; u++) {if(mask >> u & 1) continue;if(!vtomask[u][mask]) continue;if(vtomask[u][mask] >= 2) {int nxtmask = mask | (1 << u);if(chkmin(dp[nxtmask], dp[mask] + 2)) {pre[nxtmask][0] = mask;pre[nxtmask][1] = u;pre[nxtmask][2] = -1;}}for(int v = u + 1; v < n; v++) {if(mask >> v & 1) continue;if(!vtomask[v][mask]) continue;int amask = ((1 << n) - 1) ^ mask ^ (1 << u) ^ (1 << v);for(int smask = amask; ; smask = (smask - 1) & amask) {int tmask = smask | (1 << u) | (1 << v);if(SZ(road[tmask][u][v])) {if(chkmin(dp[mask | tmask], dp[mask] + SZ(road[tmask][u][v]) + 1)) {pre[mask | tmask][0] = mask;pre[mask | tmask][1] = u;pre[mask | tmask][2] = v;}}if(!smask) break;}}}}printf("%d\n", dp[(1 << n) - 1]);int mask = (1 << n) - 1;while(mask != 1) {int pmask = pre[mask][0];int u = pre[mask][1];int v = pre[mask][2];if(~v) {int tmask = mask ^ pmask;for(int i = 1; i < SZ(road[tmask][u][v]); i++)ans.push_back(mk(road[tmask][u][v][i - 1], road[tmask][u][v][i]));for(int i = 0; i < n; i++) {if((pmask >> i & 1) && G[u][i]) {ans.push_back(mk(i, u));break;}}for(int i = 0; i < n; i++) {if((pmask >> i & 1) && G[v][i]) {ans.push_back(mk(i, v));break;}}} else {for(int i = 0, c = 2; c; i++) {if(G[u][i] && (pmask >> i & 1)) {ans.push_back(mk(u, i));c--;}}}mask = pmask;}for(auto& t : ans) printf("%d %d\n", t.fi + 1, t.se + 1);return 0;
}/*
*/