#include <bits/stdc++.h>
using namespace std;

const int N=1000050;
int deg[N];
int main(){
	int n,m;
	scanf("%i %i",&n,&m);
	for(int i=1;i<=m;i++){
		int u,v;
		scanf("%i %i",&u,&v);
		deg[u]++;
		deg[v]++;
	}
	vector<int> ids;
	for(int i=0;i<n;i++)ids.push_back(i);
	sort(ids.begin(),ids.end(),[&](int i,int j){return deg[i]>deg[j];});
	int need=n*2-2;
	int now=m*2;
	int ans=0;
	for(int i:ids){
		if(need<now){
			int take=min(deg[i]-1,now-need);
			now-=take;
			deg[i]-=take;
			ans++;
		}
	}
	sort(ids.begin(),ids.end(),[&](int i,int j){return deg[i]>deg[j];});
	vector<pair<int,int>> edges;
	int ptr=0;
	for(int i=0;i<ids.size();i++){
		while(deg[ids[i]]){
			ptr++;
			deg[ids[ptr]]--;
			deg[ids[i]]--;
			edges.push_back({ids[i],ids[ptr]});
		}
	}
	printf("%i\n",ans);
	printf("%i %i\n",n,n-1);
	for(auto p:edges)printf("%i %i\n",p.first,p.second);
	return 0;
}