#include<bits/stdc++.h>
#define For(i,a,b) for(int i=(a);i<=(b);++i)
#define Rof(i,a,b) for(int i=(a);i>=(b);--i)
using namespace std;
const int Maxn=2e3;

struct Node{int frm,to,nxt,id;} Edge[Maxn*2+5];
int tot,Head[Maxn+5],h[Maxn+5];
inline void Addedge(int x,int y,int id)
{
    Edge[++tot]=(Node){x,y,Head[x],id},Head[x]=tot;
    Edge[++tot]=(Node){y,x,Head[y],id},Head[y]=tot;
}

int n,m,Mod,X[Maxn+5],Y[Maxn+5],anc[Maxn+5],fat[Maxn+5],sum,cnt,all=-1;
int fa[Maxn+5],dep[Maxn+5],chk[Maxn+5],vis[Maxn+5],deg[Maxn+5];
vector<int> v[Maxn+5]; set<int> st;
vector<pair<int,vector<int>>> ans;

inline int Pow(int x,int y)
{
    int res=1;
    while(y)
    {
        if(y&1) res=1ll*res*x%Mod;
        x=1ll*x*x%Mod,y>>=1;
    }
    return res;
}
inline void dfs(int x,int f)
{
    fat[x]=f,dep[x]=dep[f]+1;
    for(int i=Head[x];i;i=Edge[i].nxt)
    {
        int y=Edge[i].to; if(dep[y]) continue;
        fa[y]=Edge[i].id,chk[Edge[i].id]=1,dfs(y,x);
    }
}
inline void dfs1(int x)
{
    st.insert(X[x]),st.insert(Y[x]);
    vis[x]=1,sum=(sum+h[x])%Mod,cnt=(cnt+1)%Mod;
    for(auto y:v[x]) if(!vis[y]) anc[y]=x,deg[x]++,dfs1(y);
}
inline void Work(int id)
{
    st.clear(),sum=0,cnt=0,dfs1(id);
    cnt=st.size(); cnt=(cnt-1+Mod)%Mod;
    if(cnt==0 && sum!=0) {cout<<-1<<endl; exit(0);}
    if(cnt!=0)
    {
        int now=1ll*(Mod-sum)*Pow(cnt,Mod-2)%Mod;
        if(all!=-1 && all!=now) {cout<<-1<<endl; exit(0);} all=now;
    }
}

int main()
{
    // freopen("1.in","r",stdin);

    cin>>n>>m>>Mod;
    For(i,1,m)
    {
        int x,y; cin>>x>>y>>h[i]; X[i]=x,Y[i]=y;
        h[i]=(Mod-h[i])%Mod,Addedge(x,y,i);
    }
    dfs(1,0);
    For(i,1,m) if(!chk[i])
    {
        int x=X[i],y=Y[i]; if(dep[x]<dep[y]) swap(x,y);
        for(int j=x;j!=y;j=fat[j]) v[i].push_back(fa[j]),v[fa[j]].push_back(i);
    }
    For(i,1,m) if(!vis[i]) Work(i);
    if(all!=-1)
    {
        vector<int> w;
        For(i,1,m) if(chk[i]) w.push_back(i),h[i]=(h[i]+all)%Mod;
        ans.emplace_back(all,w);
    }
    // memset(vis,0,sizeof(vis));
    // For(i,1,m) if(!vis[i])
    // {
    //     sum=cnt=0; dfs1(i);
    //     assert(!sum);
    // }
    queue<int> q; For(i,1,m) if(!deg[i]) q.push(i);
    while(!q.empty())
    {
        int x=q.front(),y=anc[x]; q.pop();
        if(h[x])
        {
            vector<int> w1,w2;
            int k=(Mod-h[x])%Mod; h[x]=(h[x]+k)%Mod,h[y]=(h[y]-k+Mod)%Mod;
            For(i,1,m) if(i!=x && (chk[i] || i==y)) w2.push_back(i);
            For(i,1,m) if(i!=y && (chk[i] || i==x)) w1.push_back(i);
            ans.emplace_back(k,w1),ans.emplace_back((Mod-k)%Mod,w2);
        } if(y && --deg[y]==0) q.push(y);
    }
    cout<<ans.size()<<endl;
    for(auto [k,w]:ans) {cout<<k<<' '; for(auto i:w) cout<<i<<' '; cout<<endl;}
    return 0;
}