#include <bits/stdc++.h>
using namespace std;
const int N=5e4+10;
int n,m,w,f[N],s[N];
struct node {
    int x,y,z;
} e[N],q[N]; 
int find(int x)
{
    if (f[x]==x) return x;
    s[x]=s[f[x]];
    return f[x]=find(f[x]);
}
int cmp(node x,node y)
{
    return x.z<y.z;
}
int main() {
    freopen("hnoi2010_city.in","r",stdin);
    freopen("hnoi2010_city.out","w",stdout); 
    ios::sync_with_stdio(0),cin.tie(0);
    cin>>n>>m>>w;
    for (int i=1;i<=m;i++) cin>>e[i].x>>e[i].y>>e[i].z;
    while (w--)
    {
        int x,y;
        cin>>x>>y;e[x].z=y;
        for (int i=1;i<=m;i++) q[i]=e[i];
        for (int i=1;i<=n;i++) f[i]=i,s[i]=1;
        sort(q+1,q+m+1,cmp);
        int sz=n;
        long long ans=0;
        for (int i=1;i<=n;i++)
        {
            int fx=find(q[i].x),fy=find(q[i].y);
            if (fx!=fy)
            {
                if (s[fx]>s[fy]) swap(fx,fy); 
                f[fx]=fy,ans+=q[i].z,sz--,s[fy]+=s[fx];
            }
            if (sz==1) break;
        }
        cout<<ans<<"\n";
    }
}