#include<bits/stdc++.h>
#define int long long
using namespace std;
vector<vector<pair<int,int> > > n1;
signed main(){
int n,m,q;
cin>>n>>m>>q;
n1.resize(n);
for (int i = 0;i<m;i++){
int a,b,c;
cin>>a>>b>>c;
n1[a].push_back(make_pair(b,c));
n1[b].push_back(make_pair(a,c));
}
for (int i = 0;i<q;i++){
int l,r;
cin>>l>>r;
int ans = 0;
vector<int> d;
vector<int> d1;
d1.assign(n,0);
d.assign(n,1e9);
int ans1 = r-l+1;
priority_queue<pair<int,pair<int,int> >, vector<pair<int,pair<int,int> > >, greater<pair<int,pair<int, int> > > > pq;
for (int j = l;j<=r;j++){
d[j] = 0;
d1[j] = 1;
for (int k = 0;k<n1[j].size();k++){
pq.push(make_pair(n1[j][k].second,make_pair(n1[j][k].first,n1[j][k].second)));
}
}
while (!pq.empty()){
int a = pq.top().first;
int b = pq.top().second.first;
int c = pq.top().second.second;
pq.pop();
if (d1[b]==1) continue;
d[b] = c;
ans = ans+a;
cout<<a<<" "<<b<<" "<<c<<"\n";
for (int j = 0;j<n1[b].size();j++){
if (d1[n1[b][j].first]==0){
pq.push(make_pair(n1[b][j].second,make_pair(n1[b][j].first,n1[b][j].second+c)));
cout<<n1[b][j].second<<" "<<n1[b][j].first<<"\n";
}
}
}
cout<<ans<<"\n";
}
return 0;
}
