#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N=100010;
int n,m,q,f[N];
struct node {
    int u,v;
    ll w;
}a[N],b[N];
bool cmp (node x,node y) {
    return x.w<y.w;
}
int find (int x) {
    if (f[x]==x) return x;
    return f[x]=find(f[x]);
}

int main () {
    freopen("hnoi2010_city.in","r",stdin);
    freopen("hnoi2010_city.out","w",stdout);
    ios::sync_with_stdio(0);
    cin.tie(0),cout.tie(0);
    cin >> n >> m >> q;
    for (int i=1;i<=m;i++) cin >> a[i].u >> a[i].v >> a[i].w;
    while (q--) {
        int x,y;
        ll ans=0;
        cin >> x >> y;
        a[x].w=y;
        for (int i=1;i<=m;i++) b[i]=a[i];
        sort(b+1,b+1+m,cmp);
        for (int i=1;i<=n;i++) f[i]=i;
        for (int i=1;i<=m;i++) {
            int u=b[i].u,v=b[i].v;
            if (find(u)!=find(v)) {
                f[find(u)]=find(v);
                ans+=b[i].w;
            }
        }
        cout << ans <<endl;
    }
    return 0;
}