#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
typedef long long ll;
typedef pair <int, ll> pin;const int N = 2e4 + 5;
const int M = 5e4 + 5;
const int Lg = 20;
const ll inf = 1LL << 60;int n, m, qn, ufs[N], siz[N], pos[M], sum[Lg];
ll val[M], ans[M];
pin q[M];struct Edge {int u, v, id;ll val;friend bool operator < (const Edge &x, const Edge &y) {return x.val < y.val;}} e[Lg][M], c[M], t[M];template <typename T>
inline void read(T &X) {X = 0; char ch = 0; T op = 1;for(; ch > '9' || ch < '0'; ch = getchar())if(ch == '-') op = -1;for(; ch >= '0' && ch <= '9'; ch = getchar())X = (X << 3) + (X << 1) + ch - 48;X *= op;
}inline int find(int x) {return ufs[x] == x ? x : ufs[x] = find(ufs[x]);
}inline void merge(int x, int y) {int fx = find(x), fy = find(y);if(fx == fy) return;if(siz[fx] < siz[fy]) ufs[fx] = fy, siz[fy] += siz[fx];else ufs[fy] = fx, siz[fx] += siz[fy];
}inline void clear(int tot) {for(int i = 1; i <= tot; i++) {ufs[t[i].u] = t[i].u;ufs[t[i].v] = t[i].v;siz[t[i].u] = siz[t[i].v] = 1;}
}inline void cont(int &tot, ll &nowVal) {int cnt = 0;clear(tot);sort(t + 1, t + 1 + tot);for(int i = 1; i <= tot; i++) {int u = find(t[i].u), v = find(t[i].v);if(u == v) continue;merge(u, v);c[++cnt] = t[i];}for(int i = 1; i <= cnt; i++) {ufs[c[i].u] = c[i].u;ufs[c[i].v] = c[i].v;siz[c[i].u] = siz[c[i].v] = 1;}for(int i = 1; i <= cnt; i++) {if(c[i].val == -inf) continue;int u = find(c[i].u), v = find(c[i].v);if(u == v) continue;merge(u, v);nowVal += c[i].val;    }cnt = 0;for(int i = 1; i <= tot; i++) {int u = find(t[i].u), v = find(t[i].v);if(u == v) continue;c[++cnt] = t[i];pos[t[i].id] = cnt;c[cnt].u = ufs[t[i].u];c[cnt].v = ufs[t[i].v];}for(int i = 1; i <= cnt; i++) t[i] = c[i];tot = cnt;
}void redu(int &tot) {int cnt = 0;clear(tot);sort(t + 1, t + 1 + tot);for(int i = 1; i <= tot; i++) {if(find(t[i].u) != find(t[i].v)) {merge(t[i].u, t[i].v);c[++cnt] = t[i];pos[t[i].id] = cnt;} else if(t[i].val == inf) {c[++cnt] = t[i];pos[t[i].id] = cnt;}}for(int i = 1; i <= cnt; i++) t[i] = c[i];tot = cnt;
}void solve(int l, int r, int now, ll nowVal) {int tot = sum[now];if(l == r) val[q[l].first] = q[l].second;for(int i = 1; i <= tot; i++)e[now][i].val = val[e[now][i].id];for(int i = 1; i <= tot; i++)t[i] = e[now][i], pos[e[now][i].id] = i;if(l == r) {ans[l] = nowVal;sort(t + 1, t + 1 + tot);clear(tot);for(int i = 1; i <= tot; i++) {int u = find(t[i].u), v = find(t[i].v);if(u == v) continue;merge(u, v);ans[l] += t[i].val;}return;}for(int i = l; i <= r; i++)t[pos[q[i].first]].val = -inf;cont(tot, nowVal);for(int i = l; i <= r; i++)t[pos[q[i].first]].val = inf;redu(tot);++now;for(int i = 1; i <= tot; i++)e[now][i] = t[i];sum[now] = tot;int mid = (l + r) / 2;solve(l, mid, now, nowVal);solve(mid + 1, r, now, nowVal);
}int main() {
//    freopen("1.in", "r", stdin);
    read(n), read(m), read(qn);for(int i = 1; i <= m; i++) {read(e[0][i].u), read(e[0][i].v), read(e[0][i].val);e[0][i].id = i;val[i] = e[0][i].val;}for(int i = 1; i <= qn; i++)read(q[i].first), read(q[i].second);sum[0] = m;solve(1, qn, 0, 0LL);for(int i = 1; i <= qn; i++)printf("%lld\n", ans[i]);return 0;
}