#pragma comment(linker, "/STACK:1024000000,1024000000")

#include<cstdio>

#include<cstring>

#include<cmath>

#include<algorithm>

#include<vector>

#include<map>

#include<set>

#include<queue>

#include<stack>

#include<ctime>

#include<iostream>

using namespace std;

typedef long long LL;

const double pi=acos(-1.0),eps=1e-;

void File()

{

    freopen("D:\\in.txt","r",stdin);

    freopen("D:\\out.txt","w",stdout);

}

template <class T>

inline void read(T &x)

{

    char c = getchar();

    x = ;

    while(!isdigit(c)) c = getchar();

    while(isdigit(c))

    {

        x = x *  + c - '';

        c = getchar();

    }

}

int T,n,m,ans,cnt;

vector<int>v[];

int f[];

int ss[],ee[],t[][],p[][];

void dfs(int x)

{

    for(int i=v[x].size()-;i>=;i--)

    {

        if(t[x][v[x][i]]==) continue;

        t[x][v[x][i]]=t[v[x][i]][x]=;

        ss[cnt]=x; ee[cnt]=v[x][i]; cnt++;

        dfs(v[x][i]);

    }

}

int main()

{

    cin>>T;

    for(int cas=;cas<=T;cas++)

    {

        cin>>n>>m;

        for(int i=;i<=n+;i++) v[i].clear();

        memset(f,,sizeof f);

        memset(p,,sizeof p);

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

        {

            int a,b; cin>>a>>b;

            v[a].push_back(b);

            v[b].push_back(a);

            f[a]++; f[b]++;

            p[a][b]=p[b][a]=;

        }

        ans=; vector<int>x;

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

        {

            if(f[i]%==) ans++;

            else x.push_back(i);

        }

        for(int i=;i<x.size();i++)

        {

            v[n+].push_back(x[i]);

            v[x[i]].push_back(n+);

        }

        memset(t,,sizeof t); cnt=;

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

        printf("%d\n",ans);

        for(int i=;i<m+(n-ans);i++)

        {

            if(p[ss[i]][ee[i]]==)

                printf("%d %d\n",ss[i],ee[i]);

        }

    }

    return ;

}