bool home = 0;
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll INF = (ll)1e18 + 7;
struct SegmentTree {
vector<ll> tree;
vector<ll> lazy;
int n;
void init(int nn) {
n = nn;
tree.resize(4 * (n + 7), 0);
lazy.resize(4 * (n + 7), 0);
}
void add(int v, int tl, int tr, int l, int r, ll x) {
if (tr < l || r < tl) {
return;
}
if (l <= tl && tr <= r) {
tree[v] += x;
lazy[v] += x;
return;
}
int tm = (tl + tr) / 2;
add(2 * v, tl, tm, l, r, x);
add(2 * v + 1, tm + 1, tr, l, r, x);
tree[v] = max(tree[2 * v], tree[2 * v + 1]) + lazy[v];
}
ll getmax(int v, int tl, int tr, int l, int r) {
if (tr < l || r < tl) {
return -INF;
}
if (l <= tl && tr <= r) {
return tree[v];
}
int tm = (tl + tr) / 2;
return max(getmax(2 * v, tl, tm, l, r), getmax(2 * v + 1, tm + 1, tr, l, r)) + lazy[v];
}
void add(int l, int r, ll x) {
add(1, 1, n, l, r, x);
}
ll getmax(int l, int r) {
return getmax(1, 1, n, l, r);;
}
};
const int N = (int)1e5 + 7;
const int K = 20;
int n;
int q;
ll w;
int sum_edge[N];
ll val_edge[N];
vector<int> gindex[N];
SegmentTree trees[K];
bool blocked[N];
int sub[N];
int total_under;
void build_sub(int a, int p = -1) {
sub[a] = 1;
for (auto& I : gindex[a]) {
int b = sum_edge[I] - a;
if (b == p || blocked[b]) {
continue;
}
build_sub(b, a);
sub[a] += sub[b];
}
}
int fcen(int a, int p = -1) {
int mx = total_under - sub[a];
for (auto& I : gindex[a]) {
int b = sum_edge[I] - a;
if (b == p || blocked[b]) {
continue;
}
mx = max(mx, sub[b]);
}
if (mx <= total_under / 2) {
return a;
}
for (auto& I : gindex[a]) {
int b = sum_edge[I] - a;
if (b == p || blocked[b]) {
continue;
}
if (mx == sub[b]) {
return fcen(b, a);
}
}
}
int low[K][N];
int high[K][N];
int ord[K][N];
int where[K][N];
int vrt[K][N];
int top[K];
vector<ll> all;
vector<int> where2;
vector<pair<int, int>> seg;
vector<multiset<ll>> s;
int kek = -1;
int kek2 = -1;
multiset<int> tog;
void prep(int a, int p, int level) {
sub[a] = 1;
ord[level][++top[level]] = a;
low[level][a] = top[level];
for (auto& I : gindex[a]) {
int b = sum_edge[I] - a;
if (b == p || blocked[b]) {
continue;
}
where[level][I] = kek;
vrt[level][I] = b;
prep(b, a, level);
sub[a] += sub[b];
}
high[level][a] = top[level];
}
void add(int i, ll delta) {
for (int level = 0; level < K; level++) {
if (level != 0) {
///continue; /// delete this line urgently !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
}
if (where[level][i] == -1) {
continue;
}
int b = vrt[level][i];
int l = low[level][b], r = high[level][b];
{
ll cur = 0;
if ((int)s[where2[where[level][i]]].size() == 0) {}
else
if ((int)s[where2[where[level][i]]].size() == 1) {
cur = *s[where2[where[level][i]]].begin();
}
else {
auto it = s[where2[where[level][i]]].end();
it--;
cur += *it;
it--;
cur += *it;
}
if (tog.count(cur)) {
tog.erase(tog.find(cur));
}
}
s[where2[where[level][i]]].erase(s[where2[where[level][i]]].find(trees[level].getmax(seg[where[level][i]].first, seg[where[level][i]].second)));
trees[level].add(l, r, delta);
all[where[level][i]] = trees[level].getmax(seg[where[level][i]].first, seg[where[level][i]].second);
s[where2[where[level][i]]].insert(trees[level].getmax(seg[where[level][i]].first, seg[where[level][i]].second));
{
ll cur = 0;
if ((int)s[where2[where[level][i]]].size() == 0) {}
else
if ((int)s[where2[where[level][i]]].size() == 1) {
cur = *s[where2[where[level][i]]].begin();
}
else {
auto it = s[where2[where[level][i]]].end();
it--;
cur += *it;
it--;
cur += *it;
}
tog.insert(cur);
}
}
}
void build_centroid(int a, int level) {
assert(level < 20);
build_sub(a);
total_under = sub[a];
a = fcen(a);
blocked[a] = 1;
kek2++;
s.push_back({});
for (auto& I : gindex[a]) {
int b = sum_edge[I] - a;
if (blocked[b]) {
continue;
}
kek++;
all.push_back(0);
vrt[level][I] = b;
where[level][I] = kek;
prep(b, a, level);
seg.push_back({ low[level][b], high[level][b] });
where2.push_back(kek2);
s.back().insert(0);
}
for (auto& I : gindex[a]) {
int b = sum_edge[I] - a;
if (blocked[b]) {
continue;
}
build_centroid(b, level + 1);
}
}
ll get_diam() {
ll sol = 0;
for (auto& s2 : s) {
auto it = s2.end();
ll cur = 0;
it--;
cur += *it;
it--;
cur += *it;
sol = max(sol, cur);
}
return sol;
}
int xx[N], yy[N];
int main() {
if (home == 0) {
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
}
else {
freopen("input.txt", "r", stdin);
}
cin >> n >> q >> w;
for (int i = 0; i < K; i++) {
for (int j = 0; j < N; j++) {
where[i][j] = -1;
}
trees[i].init(n);
}
for (int i = 1; i < n; i++) {
int a, b, c;
cin >> a >> b >> c;
xx[i] = a;
yy[i] = b;
sum_edge[i] = a + b;
gindex[a].push_back(i);
gindex[b].push_back(i);
val_edge[i] = c;
}
build_centroid(1, 0);
for (int i = 1; i < n; i++) {
add(i, val_edge[i]);
}
ll last = 0;
for (int iq = 1; iq <= q; iq++) {
int d, e;
cin >> d >> e;
d = (d + last) % (n - 1) + 1;
e = (e + last) % w;
add(d, -val_edge[d] + e);
val_edge[d] = e;
if (tog.empty()) {
last = 0;
}
else {
auto it = tog.end();
it--;
last = *it;
}
cout << last << "\n";
}
return 0;
}
