#include<bits/stdc++.h>
#define int long long
#define pb push_back
#define fo(ioo,aoo,boo) for(int ioo=aoo;ioo<=boo;ioo++)
#define PII pair<int,int>
#define N 51451
using namespace std;

int fa[N];

struct edge{
    int x,y,w;
    bool operator<(const edge p){
        return w<p.w;
    }
}e[N],ee[N];

int getfa(int x){
    if(x==fa[x])return x; 
    return fa[x]=getfa(fa[x]);
}

void merge(int x,int y){
    fa[getfa(x)]=getfa(y);
    return;
}

int n,m,q;

void kruskal(){
    fo(i,1,n)fa[i]=i;
    fo(i,1,m)ee[i]=e[i];
    sort(ee+1,ee+m+1);
    int ans=0,cnt=0,x,y,w;
    fo(i,1,m){
        if(cnt==n-1)break;
        x=ee[i].x;y=ee[i].y;w=ee[i].w;
        if(getfa(x)!=getfa(y)){
            ans+=w;
            merge(x,y);
            cnt++;
        }
    }
    cout<<ans<<"\n";
}

signed main(){
    ios::sync_with_stdio(0);cin.tie(0);
    freopen("hnoi2010_city.in","r",stdin);freopen("hnoi2010_city.out","w",stdout);
    cin>>n>>m>>q;
    fo(i,1,m)cin>>e[i].x>>e[i].y>>e[i].w;
    while(q--){
        int k,d;
        cin>>k>>d;
        e[k].w=d;
        kruskal();
    }
    return 0;
}