#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
#define pll pair <ll,ll>
#define fi first
#define se second
#define sz(a) (ll((a).size()))
#define BIT(mask,i) (((mask) >> (i))&1LL)
#define MASK(i) (1LL << (i))
ll n,m;
vector <ll> g[1010];
int main(){
    ios_base::sync_with_stdio(0);cin.tie(nullptr);cout.tie(nullptr);
    cin>>n>>m;
    vector <pll> edge;
    for (ll i = 1;i <= m;i ++){
        ll u,v;
        cin>>u>>v;
        g[u].push_back(v);
        g[v].push_back(u);
        edge.push_back({u,v});
    }
    ll cnt[6]={};
    for (ll i = 1;i <= n;i ++){
        if (sz(g[i])<6)cnt[sz(g[i])]^=1;
    }
    if (cnt[0]+cnt[1]+cnt[2]+cnt[3]+cnt[4]!=0){
        cout<<"mark\n";
        vector <pll> del;
        for (ll i = 0;i < 5;i ++){
//            cout<<i<<endl;
            ll sum = 0;
            for (ll j = 1;j <= n;j ++)sum += sz(g[j])==i;
            if (sum%2){
                bool ok = 0;
                for (ll j = 1;j <= n && !ok;j ++){
                    if (sz(g[j])==i+1){
                        for (auto x:g[j]){
                            if (sz(g[x])>i+1){
                                del.push_back({j,x});
//                                cout<<i<<' '<<j<<' '<<x<<' '<<sz(g[j])<<' '<<sz(g[x])<<'\n';
                                for (ll k = 0;k < sz(g[j]);k++){
                                    if (g[j][k]==x){
                                        g[j].erase(g[j].begin()+k);
                                    }
                                }
                                for (ll k = 0;k < sz(g[x]);k++){
                                    if (g[x][k]==j){
                                        g[x].erase(g[x].begin()+k);
                                    }
                                }
                                ok = 1;
                                break;
                            }
                        }
                    }
                }
                assert(ok);
            }
        }
        memset(cnt,0,sizeof cnt);
        for (ll i = 1;i <= n;i ++){
            if (sz(g[i])<6)cnt[sz(g[i])]^=1;
        }
        assert(cnt[0]+cnt[1]+cnt[2]+cnt[3]+cnt[4]==0);
        cout<<sz(del)<<'\n';
        for (auto x:del)cout<<x.fi<<' '<<x.se<<'\n';
    }
    else{
        cout<<"ok";
    }
//    cout<<even<<'\n';
}