#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 10;
int n, m, q, x[N], y[N], z[N], f[N], tmp, p[N];
long long ans;
int found(int x) {
    return f[x] == x ? x : f[x] = found(f[x]);
}
void MST() {
    ans = 0, tmp = n;
    for (int i = 1; i <= n; i++) f[i] = i;
    for (int i = 1, u, v; i <= m; i++) {
        u = x[p[i]], v = y[p[i]];
        if (found(u) != found(v)) {
            f[found(u)] = found(v);
            ans += z[p[i]];
            if ((--tmp) == 1) break; 
        }
    } 
    cout << ans << '\n';
    return;
}
void Sort() {
    if (m <= 6000) {
        sort(p + 1, p + 1 + m, [&](int u, int v) {
            return z[u] < z[v];
        });
    } else if (q <= 8000) {
        bool flag = 1;
        for (int i = 1; i < m; i++) {
            if (z[p[i]] > z[p[i + 1]]) {
                swap(p[i], p[i + 1]);
                flag = 0;
            } else if (!flag) break;
        }
    } else {
        sort(p + 1, p + 1 + m, [&](int u, int v) {
            return z[u] < z[v];
        });
    } 
    return;
}
int main() {
    freopen("hnoi2010_city.in", "r", stdin);
    freopen("hnoi2010_city.out", "w", stdout);
    cin >> n >> m >> q;
    for (int i = 1; i <= m; i++) {
        cin >> x[i] >> y[i] >> z[i];
    }
    for (int i = 1; i <= m; i++) {
        p[i] = i;
    }
    sort(p + 1, p + 1 + m, [&](int u, int v) {
        return z[u] < z[v];
    });
    int k, d;
    for (int _ = 1; _ <= q; _++) {
        cin >> k >> d;
        z[k] = d;
        Sort();
        MST();
    } 
    return 0;
}