#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef struct {
int idx;
ll val;
} pil;
int n, q;
ll w;
ll edges[101010][3];
vector<pil> adj[101010];
int ch[101010], sz[101010];
struct subtree {
int cent, tot, r, d;
vector<pil> ord;
unordered_map<int, int> in, out, depth, dir, child;
void ett(int v, ll dis, int par = -1) {
ord[++r] = {v, dis}; in[v] = r;
if (par != -1) dir[v] = d;
for (int i = 0; i < adj[v].size(); i++) {
int u = adj[v][i].idx;
if (u == par) continue;
if (ch[u] == 1) continue;
depth[u] = depth[v] + 1;
if (par == -1) d = u;
ett(u, dis + adj[v][i].val, v);
}
out[v] = r;
}
struct maxseg {
vector<pil> tree;
vector<ll> lazy;
pil mer(pil lt, pil rt) {
if (lt.val > rt.val) return lt;
if (lt.val < rt.val) return rt;
if (lt.val == rt.val) {
if (lt.idx > rt.idx) return lt;
else return rt;
}
}
void prop(int v, int st, int ed) {
tree[v].val += lazy[v];
if (st != ed) {
lazy[2*v] += lazy[v];
lazy[2*v+1] += lazy[v];
}
lazy[v] = 0;
}
void init(int v, int st, int ed, vector<pil>* ord) {
if (st == ed) {
tree[v] = (*ord)[st];
lazy[v] = 0;
return;
}
int mid = (st + ed) / 2;
init(2*v, st, mid, ord);
init(2*v+1, mid+1, ed, ord);
tree[v] = mer(tree[2*v], tree[2*v+1]);
}
void upd(int v, int st, int ed, int lt, int rt, ll diff) {
prop(v, st, ed);
if (lt <= st && ed <= rt) {
lazy[v] = diff;
prop(v, st, ed);
return;
}
if (st > rt || lt > ed) return;
int mid = (st + ed) / 2;
upd(2*v, st, mid, lt, rt, diff);
upd(2*v+1, mid+1, ed, lt, rt, diff);
tree[v] = mer(tree[2*v], tree[2*v+1]);
}
pil get(int v, int st, int ed, int lt, int rt) {
prop(v, st, ed);
if (lt <= st && ed <= rt) return tree[v];
if (st > rt || lt > ed) return {0, 0};
int mid = (st + ed) / 2;
return mer(get(2*v, st, mid, lt, rt), get(2*v+1, mid+1, ed, lt, rt));
}
} seg;
void init() {
r = 0;
for (int i = 0; i <= tot; i++) ord.push_back({0, 0});
seg.tree.resize(4*tot);
seg.lazy.resize(4*tot);
ett(cent, 0);
seg.init(1, 1, tot, &ord);
}
int update(int d, ll e) {
int v = (depth[edges[d][0]] > depth[edges[d][1]] ? edges[d][0] : edges[d][1]);
int u = (depth[edges[d][0]] < depth[edges[d][1]] ? edges[d][0] : edges[d][1]);
seg.upd(1, 1, tot, in[v], out[v], e - edges[d][2]);
return (u != cent ? child[dir[v]] : 0);
}
int get(ll* dst) {
pil x = seg.get(1, 1, tot, 1, tot);
int u = dir[x.idx];
pil y = seg.get(1, 1, tot, 1, in[u]-1);
pil z = seg.get(1, 1, tot, out[u]+1, tot);
*dst = max(*dst, x.val + max(y.val, z.val));
return child[u];
}
} sub[101010];
void get_sz(int v, int par = -1) {
sz[v] = 1;
for (int i = 0; i < adj[v].size(); i++) {
int u = adj[v][i].idx;
if (ch[u] == 1) continue;
if (u == par) continue;
get_sz(u, v);
sz[v] += sz[u];
}
}
int get_cent(int tot, int v, int par = -1) {
for (int i = 0; i < adj[v].size(); i++) {
int u = adj[v][i].idx;
if (ch[u] == 1) continue;
if (u == par) continue;
if (sz[u] * 2 > tot) return get_cent(tot, u, v);
}
return v;
}
int cent(int v, int tot) {
get_sz(v);
v = get_cent(tot, v);
get_sz(v);
sub[v].tot = tot;
sub[v].cent = v;
sub[v].init();
ch[v] = 1;
for (int i = 0; i < adj[v].size(); i++) {
int u = adj[v][i].idx;
if (ch[u] == 1) continue;
sub[v].child[u] = cent(u, sz[u]);
}
return v;
}
void update(int cent, int d, ll e) {
while (sub[cent].tot > 1) {
cent = sub[cent].update(d, e);
}
}
void get(int cent, ll* dst) {
while (sub[cent].tot > 1) {
cent = sub[cent].get(dst);
}
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cin >> n >> q >> w;
for (int i = 1; i < n; i++) {
int a, b; ll c;
cin >> a >> b >> c;
edges[i][0] = a;
edges[i][1] = b;
edges[i][2] = c;
adj[a].push_back({b, c});
adj[b].push_back({a, c});
}
int CENT = cent(1, n);
ll last = 0;
while (q--) {
int d; ll e;
cin >> d >> e;
d = (d + last) % (n - 1) + 1;
e = (e + last) % w;
update(CENT, d, e);
edges[d][2] = e;
last = -1;
get(CENT, &last);
cout << last << "\n";
}
return 0;
}
