#include <bits/stdc++.h>
#define int long long
using namespace std;

const int N = 20010, M = 50010;
int n, m, q, fa[N], ans;
struct edge{
	int u, v, w, i;
} g[M];

bool cmp(edge x, edge y) {
	return x.w < y.w;
}

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

void kruskal() {
	sort(g+1, g+1+m, cmp);
	for (int i = 1; i <= n; i++) fa[i] = i;
	for (int i = 1; i <= m; i++) {
		int fu = find(g[i].u);
		int fv = find(g[i].v);
		if (fu == fv) continue;
		ans += g[i].w;
		fa[fu] = fv;
	}
}

signed main() {
	ios::sync_with_stdio(0);
	cin.tie(0), cout.tie(0);
	freopen("hnoi2010_city.in", "r", stdin);
	freopen("hnoi2010_city.out", "w", stdout);
	cin >> n >> m >> q;
	for (int i = 1; i <= m; i++) {
		int x, y, z;
		cin >> x >> y >> z;
		g[i] = {x, y, z, i};
	}
	for (int i = 1; i <= q; i++) {
		int x, y;
		cin >> x >> y;
		for (int j = 1; j <= m; j++) if (g[j].i == x) g[j].w = y;
		ans = 0;
		kruskal();
		cout << ans << "\n";
	}
	return 0;
}