1 #include <map>  2 #include <set>  3 #include <stack>  4 #include <queue>  5 #include <cmath>  6 #include <ctime>  7 #include <string>  8 #include <vector>  9 #include <cstdio> 10 #include <cstdlib> 11 #include <cstring> 12 #include <cassert> 13 #include <iostream> 14 #include <algorithm> 15 #pragma comment(linker,"/STACK:102400000,102400000") 16 using namespace std; 17  18 #define N 1000 19 #define E 50000 20 #define LL long long 21 #define lson l,m,rt<<1 22 #define rson m+1,r,rt<<1|1  23 #define clr(x,v) memset(x,v,sizeof(x)); 24 #define bitcnt(x) __builtin_popcount(x) 25 #define rep(x,y,z) for (int x=y;x<=z;x++) 26 #define repd(x,y,z) for (int x=y;x>=z;x--) 27 const int mo  = 1000000007; 28 const int inf = 0x3f3f3f3f; 29 const int INF = 2000000000; 30 /**************************************************************************/  31  32 int T,n,m,sum; 33 int lt[N],deg[N],f[N],dict[E]; 34 struct line{ 35     int u,v,nt,flag; 36 }eg[E]; 37 void add(int u,int v) 38 { 39     eg[++sum]=(line){u,v,lt[u],0}; lt[u]=sum; deg[v]++; 40 } 41 vector <int> vct,path; 42 stack <int> Q; 43 void dfs(int u) 44 { 45     int v=0; 46     Q.push(u); 47     f[u]=1; 48     for (int i=lt[u];i;i=eg[i].nt) 49     { 50         if (eg[i].flag) continue; 51         eg[i].flag=eg[i^1].flag=1; dict[i/2]=i; lt[u]=i; 52         v=eg[i].v;  53         dfs(v); 54         break; 55     } 56 } 57 void work(int S) 58 { 59     while (!Q.empty()) Q.pop(); 60     Q.push(S); 61     while (!Q.empty()) 62     { 63         int u=Q.top(),flag=0; Q.pop(); 64         for (int i=lt[u];i;i=eg[i].nt) 65         { 66             if (eg[i].flag) continue; 67             flag=1; 68             break;         69         } 70         if (flag) dfs(u); else path.push_back(u); 71     } 72 } 73 int main() 74 { 75     cin>>T; 76     while (T--) 77     { 78         cin>>n>>m;  79         int ans=n; 80         rep(i,1,n) deg[i]=lt[i]=0; sum=1; 81         rep(i,1,m) 82         { 83             int u,v; 84             scanf("%d%d",&u,&v); 85             add(u,v); add(v,u); 86         } 87         vct.clear(); path.clear(); 88         rep(i,1,n) if (deg[i] & 1) 89         { 90             ans--; 91             vct.push_back(i); 92         } 93         for (int i=0;i<vct.size();i+=2) 94         { 95             add(vct[i],vct[i+1]); 96             add(vct[i+1],vct[i]); 97         } 98         clr(f,0); 99         rep(i,1,n) if (f[i]==0) work(i);100         printf("%d\n",ans);101         rep(i,1,m) printf("%d %d\n",eg[dict[i]].u,eg[dict[i]].v);102         //for (auto v:path) printf("%d ",v);103     }104 }