#include<iostream>
#include<vector>
#include<algorithm>
#include<cmath>
using namespace std;
int n,m;
int used[1001];
int vh[1001],izh[1001],ost;
int a[100000],b[100000],usedr[100001];
void read()
{
     cin>>n>>m;
     for(int i=0;i<m;i++)
     {
             cin>>a[i]>>b[i];
             used[a[i]]++;
             used[b[i]]++;
     }
     for(int i=1;i<=n;i++)
     {
            // cout<<used[i]<<endl;
             if(used[i]%2==0){vh[i]=used[i]/2;izh[i]=used[i]/2;}
             else
             {
                 if(!ost)
                 {
                 vh[i]=used[i]/2;
                 izh[i]=used[i]/2;
                 izh[i]++;
                 ost++;
                 }
                 else
                 {
                     vh[i]=used[i]/2;
                     izh[i]=used[i]/2;
                     vh[i]++;
                     ost--;
                 }
             }
     }
     //for(int i=1;i<=n;i++)
       //   cout<<vh[i]<<' '<<izh[i]<<endl;     
}
void razm()
{
     for(int i=1;i<=n;i++)
     if(used[i]%2==1)
     swap(vh[i],izh[i]);
}
int solve()
{
     int br=0;
     for(int i=0;i<m;i++)
         {
                 if(izh[a[i]]&&vh[b[i]])
                 {
                                        izh[a[i]]--;
                                        vh[b[i]]--;
                                        br++;
     //                                   cout<<a[i]<<' '<<b[i]<<endl;
       //                                 cout<<izh[a[i]]<<' '<<vh[b[i]]<<"hmm"<<endl;
                 }
                 else
                 if(vh[a[i]]&&izh[b[i]])
                 {
                                        vh[a[i]]--;
                                        izh[b[i]]--;
                                        swap(a[i],b[i]);br++;
         //                               cout<<a[i]<<' '<<b[i]<<endl;
           //                             cout<<izh[a[i]]<<' '<<vh[b[i]]<<"hmm"<<endl;
                 }
         }
     }
void print()
{
     cout<<"Yes"<<endl;
     for(int i=0;i<m;i++)
     cout<<a[i]<<' '<<b[i]<<endl;     
     }
int main()
{
    read();
    int test1,test2;
    test1=solve();
    if(test1==m)
    print();
    else
    while(1)
    {
    test2=solve();
    if(test2==m){print();break;}
    else
    if(test2==test1){cout<<"No"<<endl;break;}
    else
    test1=test2;
    }
    return 0;
}   
