#include <bits/stdc++.h>
#define For(i,l,r) for(int i=l; i<=r; i++)
#define IOS {cin.tie(0);cout.tie(0);ios::sync_with_stdio(0);}
using namespace std;
//find t
struct no{
    int x,y,w,id;
}ed[3005];
int fl[3005],f2[3005];
bool cmd(no n,no m){
    return (n.w==m.w)?fl[n.id]>fl[m.id]:n.w<m.w;
}
int fa[3005];
int find(int x){return fa[x]==x?x:fa[x]=find(fa[x]);}
//change
struct node{
    int y,id;
};
vector<node> v[3005];
int col[3005];
void dfs(int x,int f,int co){
    col[x]=co;
    for(auto o:v[x]){
        int id=o.id,y=o.y;
        if (fl[id]&&y!=f) dfs(y,x,co);
    }
}
int main(){
    IOS
    int n,m; cin>>n>>m;
    For(i,1,m){
        int x,y,z; cin>>x>>y>>z;
        ed[i]=no{x,y,z,i};
        v[x].push_back(node{y,i}); v[y].push_back(node{x,i});
    }
    For(i,1,n-1) fl[i]=1;
    //find t
    sort(ed+1,ed+1+m,cmd);
    For(i,1,n) fa[i]=i;
    int cnt=0;
    For(i,1,m){
        int x=ed[i].x,y=ed[i].y,id=ed[i].id;
        if (find(x)!=find(y)){
            //printf("#%d\n",id);
            fa[fa[x]]=fa[y]; ++cnt; f2[id]=1;
            if (cnt==n-1) break;
        }
    }
    //ans
    int an=0;
    For(i,1,n-1) if (!f2[i]) ++an;
    printf("%d\n",an);
    //change
    For(i,1,m){
        int x=ed[i].x,y=ed[i].y,id=ed[i].id;
        if (fl[id]&&!f2[id]){
            dfs(x,y,-1); dfs(y,x,1);
            //For(ii,1,n) printf("%d ",col[ii]); printf("\n");
            For(j,1,m){
                int xx=ed[j].x,yy=ed[j].y,idd=ed[j].id;
                if (col[xx]!=col[yy]&&!fl[idd]&&f2[idd]){
                    fl[idd]=1; fl[id]=0;
                    printf("%d %d\n",id,idd);
                    break;
                }
            }
        }
    }
    return 0;
}