#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define f first
#define s second
const ll inf = 1e18;
#define vll vector<ll>
ll n, q, w;
vector<tuple<ll, ll, ll>> edges;
vector<ll> tin, tout, par, comp, vin;
ll timer = 0;
vector<vector<ll>> g;
void dfs(ll node, ll pari) {
par[node] = pari;
tin[node] = timer++;
vin[tin[node]] = node;
for (auto it : g[node]) {
if (it == pari)
continue;
dfs(it, node);
}
tout[node] = timer - 1;
}
void dfs2(ll node, ll pari, ll id) {
comp[node] = id;
for (auto it : g[node]) {
if (it == pari)
continue;
dfs2(it, node, node == 0 ? it : id);
}
}
struct cand {
ll val;
ll id;
};
struct node {
cand a, b;
ll lazy;
};
node merge(node A, node B) {
vector<cand> v = {A.a, A.b, B.a, B.b};
sort(v.begin(), v.end(), [](cand x, cand y) { return x.val > y.val; });
node res;
res.a = v[0];
res.b = {-(ll)4e18, -1};
for (auto x : v)
if (x.id != res.a.id) {
res.b = x;
break;
}
res.lazy = 0;
return res;
}
struct Seg {
vector<node> seg;
ll sz = 1;
Seg() {
tin.resize(n), tout.resize(n), par.resize(n), comp.resize(n), vin.resize(n);
timer = 0;
dfs(0, -1);
dfs2(0, -1, -1);
for (; sz < n; sz *= 2)
;
seg.resize(2 * sz);
for (ll i = 0; i < n; i++) {
ll v = vin[i];
seg[sz + i].a = {0, comp[v]};
seg[sz + i].b = {-(ll)4e18, -1};
}
for (ll i = sz - 1; i >= 1; --i)
seg[i] = merge(seg[i * 2], seg[i * 2 + 1]);
}
void push(ll i) {
ll x = seg[i].lazy;
if (x == 0)
return;
seg[i * 2].a.val += x;
seg[i * 2].b.val += x;
seg[i * 2].lazy += x;
seg[i * 2 + 1].a.val += x;
seg[i * 2 + 1].b.val += x;
seg[i * 2 + 1].lazy += x;
seg[i].lazy = 0;
}
void update(ll i, ll l, ll r, ll a, ll b, ll w) {
if (l > b || r < a)
return;
if (l >= a && r <= b) {
seg[i].a.val += w;
seg[i].b.val += w;
seg[i].lazy += w;
return;
}
push(i);
ll mid = (l + r) / 2;
update(i * 2, l, mid, a, b, w);
update(i * 2 + 1, mid + 1, r, a, b, w);
seg[i] = merge(seg[i * 2], seg[i * 2 + 1]);
}
void update(ll node, ll w) {
ll l = tin[node], r = tout[node];
update(1, 0, sz - 1, l, r, w);
}
ll ans() {
return seg[1].a.val + seg[1].b.val;
}
};
vector<vector<pair<ll, ll>>> wg;
vector<vector<pair<ll, ll>>> adj_e;
vector<ll> deadc, szt;
ll Nsz;
void getsz(ll u, ll p) {
szt[u] = 1;
for (auto [v, id] : adj_e[u]) {
if (v == p || deadc[v])
continue;
getsz(v, u);
szt[u] += szt[v];
}
}
ll getcent(ll u, ll p, ll tot) {
for (auto [v, id] : adj_e[u]) {
if (v == p || deadc[v])
continue;
if (szt[v] * 2 > tot)
return getcent(v, u, tot);
}
return u;
}
void collect_nodes(ll u, ll p, vector<ll>& vec) {
vec.push_back(u);
for (auto [v, id] : adj_e[u]) {
if (v == p || deadc[v])
continue;
collect_nodes(v, u, vec);
}
}
struct SegC {
vector<node> seg;
ll sz = 1;
vector<ll> alive;
vector<ll> compc;
ll c;
SegC(ll cc, const vector<ll>& nodes) {
c = cc;
for (; sz < n; sz *= 2)
;
seg.resize(2 * sz);
alive.assign(n, 0);
compc.assign(n, -1);
for (auto v : nodes)
alive[v] = 1;
vector<ll> dist(n, 0);
deque<ll> dq;
dq.push_back(c);
vector<ll> vis(n, 0);
vis[c] = 1;
while (!dq.empty()) {
ll u = dq.front();
dq.pop_front();
for (auto [v, id] : wg[u]) {
if (vis[v] || deadc[v])
continue;
vis[v] = 1;
dist[v] = dist[u] + get<2>(edges[id]);
dq.push_back(v);
}
}
function<void(ll, ll, ll)> dfscomp = [&](ll u, ll p, ll id) {
compc[u] = id;
for (auto [v, eid] : adj_e[u]) {
if (v == p || deadc[v])
continue;
dfscomp(v, u, u == c ? v : id);
}
};
dfscomp(c, -1, -1);
for (ll i = 0; i < n; ++i) {
ll v = vin[i];
if (alive[v]) {
seg[sz + i].a = {dist[v], compc[v]};
} else {
seg[sz + i].a = {-(ll)4e18, -1};
}
seg[sz + i].b = {-(ll)4e18, -1};
}
for (ll i = sz - 1; i >= 1; --i)
seg[i] = merge(seg[i * 2], seg[i * 2 + 1]);
}
void push(ll i) {
ll x = seg[i].lazy;
if (x == 0)
return;
seg[i * 2].a.val += x;
seg[i * 2].b.val += x;
seg[i * 2].lazy += x;
seg[i * 2 + 1].a.val += x;
seg[i * 2 + 1].b.val += x;
seg[i * 2 + 1].lazy += x;
seg[i].lazy = 0;
}
void upd(ll i, ll l, ll r, ll a, ll b, ll w) {
if (l > b || r < a)
return;
if (l >= a && r <= b) {
seg[i].a.val += w;
seg[i].b.val += w;
seg[i].lazy += w;
return;
}
push(i);
ll mid = (l + r) / 2;
upd(i * 2, l, mid, a, b, w);
upd(i * 2 + 1, mid + 1, r, a, b, w);
seg[i] = merge(seg[i * 2], seg[i * 2 + 1]);
}
void update_range(ll l, ll r, ll w) {
if (l <= r)
upd(1, 0, sz - 1, l, r, w);
}
void update_all(ll w) {
upd(1, 0, sz - 1, 0, sz - 1, w);
}
ll ans() {
return seg[1].a.val + seg[1].b.val;
}
};
vector<SegC> segsC;
vector<ll> cent_node;
vector<ll> cent_id_of_node;
vector<vector<pair<ll, ll>>> affect;
ll build_centroid(ll root) {
getsz(root, -1);
ll c = getcent(root, -1, szt[root]);
vector<ll> nodes;
collect_nodes(c, -1, nodes);
ll idx = (ll)segsC.size();
cent_node.push_back(c);
cent_id_of_node[c] = idx;
segsC.emplace_back(SegC(c, nodes));
deadc[c] = 1;
for (auto [v, id] : adj_e[c]) {
if (deadc[v])
continue;
build_centroid(v);
}
return idx;
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n >> q >> w;
edges.resize(n - 1);
g.resize(n);
wg.assign(n, {});
adj_e.assign(n, {});
for (ll i = 0; i < n - 1; ++i) {
ll a, b, c;
cin >> a >> b >> c;
a--;
b--;
edges[i] = {a, b, c};
g[a].push_back(b);
g[b].push_back(a);
}
Seg seg;
par[0] = -1;
for (ll i = 0; i < n - 1; ++i) {
auto& [a, b, c] = edges[i];
if (par[b] != a)
swap(a, b);
seg.update(b, c);
}
wg.clear();
wg.assign(n, {});
adj_e.assign(n, {});
for (ll i = 0; i < n - 1; ++i) {
auto [a, b, c] = edges[i];
wg[a].push_back({b, i});
wg[b].push_back({a, i});
adj_e[a].push_back({b, i});
adj_e[b].push_back({a, i});
}
deadc.assign(n, 0);
szt.assign(n, 0);
cent_id_of_node.assign(n, -1);
affect.assign(n - 1, {});
build_centroid(0);
for (ll ci = 0; ci < (ll)segsC.size(); ++ci) {
ll c = cent_node[ci];
for (ll i = 0; i < n - 1; ++i) {
auto [a, b, wc] = edges[i];
ll inside = (tin[c] >= tin[b] && tin[c] <= tout[b]) ? 1 : 0;
affect[i].push_back({ci, inside});
}
}
multiset<ll> ms;
vector<ll> cur(segsC.size());
for (ll i = 0; i < (ll)segsC.size(); ++i) {
cur[i] = segsC[i].ans();
ms.insert(cur[i]);
}
ll last = 0;
while (q--) {
ll d, e;
cin >> d >> e;
ll d1 = (d + last) % (n - 1);
ll e1 = (e + last) % w;
auto& [a, b, c] = edges[d1];
ll dis = e1 - c;
c = e1;
for (auto pr : affect[d1]) {
ll ci = pr.f;
ll inside = pr.s;
ms.erase(ms.find(cur[ci]));
if (inside) {
segsC[ci].update_all(dis);
segsC[ci].update_range(tin[b], tout[b], -dis);
} else {
segsC[ci].update_range(tin[b], tout[b], dis);
}
cur[ci] = segsC[ci].ans();
ms.insert(cur[ci]);
}
last = *ms.rbegin();
cout << last << endl;
}
}
