#include 
#include 
#include 
using namespace std;


int main()
{
    int n, m, q;
    
    cin>>n>>m>>q;
    
    long long a, b, c;
    
    long long shortestpath[n][n];
    
    for(int i=0; i>a>>b>>c;
        a--;
        b--;
    shortestpath[a][b]=min(shortestpath[a][b], c);
        shortestpath[b][a] = min(shortestpath[a][b], c);
    }


    for(int k=0; k>a>>b;
            a--; b--;
            if(shortestpath[a][b] == 1e18) {
                cout << -1 << endl;
            }
      else  cout<