#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vi = vector<int>;
using ii = pair<int, int>;
struct AINT {
int n;
vector<ll> V;
AINT() {}
AINT(int N) : n(N), V(N, 0) {}
void update(int st, int dr, ll v) {
for(int i = st; i <= dr; ++i) V[i] += v;
}
ll query(int st, int dr) {
ll re = 0;
for(int i = st; i <= dr; ++i) re = max(re, V[i]);
return re;
}
};
namespace tree {
int n;
int tmr = 0;
vi niv, euler, on, sz;
vector<ll> cost;
vector<vector<ii> > L;
multiset<ll> Profi;
struct InfoCent {
multiset<ll> V;
ll profit = 0;
void change(ll a, ll b) {
Profi.erase(Profi.find(profit));
V.erase(V.find(a));
V.insert(b);
ll vm = *V.rbegin();
profit = vm;
V.erase(V.find(vm));
if(!V.empty())
profit += *V.rbegin();
V.insert(vm);
Profi.insert(profit);
}
};
vector<InfoCent> Info;
struct comp {
int st, dr, cent;
ll val;
};
vector<comp> Componente;
vector< vector<ii> > SegMuchie;
vector<vi> CompMuchie;
AINT Sol;
void init(int N) {
n = N;
niv.assign(N, 0);
on.assign(N, 1);
sz.assign(N, 0);
cost.assign(N, 0);
L.resize(N);
Info.resize(N);
SegMuchie.resize(N);
CompMuchie.resize(N);
}
void add_edge(int u, int v, int id) {
L[u].push_back({v, id});
L[v].push_back({u, id});
}
void init() {
function<void(int, int)> dfs_sz = [&](int u, int p) {
sz[u] = 1;
for(auto [it, id] : L[u])
if(it != p && on[it]) {
dfs_sz(it, u);
sz[u] += sz[it];
}
};
function<int(int, int, int)> find_c = [&](int u, int p, int sz_lim) {
for(auto [it, id] : L[u])
if(on[it] && it != p && 2 * sz[it] > sz_lim) return find_c(it, u, sz_lim);
return u;
};
function<void(int, int, int, int)> dfs_comp = [&](int u, int p, int id_par, int cur_comp) {
int in = tmr;
int nr_fii = 0;
for(auto [it, id] : L[u]) {
if(it == p || !on[it]) continue;
++nr_fii;
dfs_comp(it, u, id, cur_comp);
}
if(!nr_fii) { /// sunt o frunza, ++tmr!
++tmr;
}
int out = tmr - 1;
///id_par afecteaza {in, out}
SegMuchie[id_par].push_back({in, out});
CompMuchie[id_par].push_back(cur_comp);
};
function<void(int, int)> desc_cent = [&](int u, int parc) {
Profi.insert(0);
dfs_sz(u, -1);
int c = find_c(u, -1, sz[u]);
on[c] = 0;
for(auto [it, id] : L[c]) {
if(on[it]) {
///componenta noua
int eu = Componente.size();
int in = tmr;
dfs_comp(it, c, id, eu);
int out = tmr - 1;
Componente.push_back({in, out, c, 0});
Info[c].V.insert(0);
}
}
for(auto [it, id] : L[c]) {
if(on[it]) {
desc_cent(it, c);
}
}
};
desc_cent(0, -1);
Sol = AINT(tmr);
}
void update(int id, ll w) {
w -= cost[id];
cost[id] += w;
for(auto [st, dr] : SegMuchie[id]) {
Sol.update(st, dr, w);
}
for(auto comp : CompMuchie[id]) {
auto &[st, dr, cent, val] = Componente[comp];
ll v2 = Sol.query(st, dr);
Info[cent].change(val, v2);
val = v2;
}
}
ll diam() {
return *Profi.rbegin();
}
};
struct edge {
int u, v;
ll w;
};
int main() {
int n, q;
ll w_max;
cin >> n >> q >> w_max;
tree::init(n);
vector<edge> E;
for(int i = 1; i < n; ++i) {
int u, v;
ll w;
cin >> u >> v >> w;
--u; --v;
E.push_back({u, v, w});
tree::add_edge(u, v, i - 1);
}
tree::init();
for(int i = 0; i < E.size(); ++i)
tree::update(i, E[i].w);
ll last = 0;
for(int i = 0; i < q; ++i) {
ll d, e;
cin >> d >> e;
d = (d + last) % (n - 1);
e = (e + last) % w_max;
tree::update((int)d, e);
cout << (last = tree::diam()) << "\n";
}
return 0;
}
