#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pii;
#define fi first
#define se second
#define mp make_pair
#define fastIO ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
const ll N = (ll)1e5 + 5;
ll ww[N];
vector<pii> T[N];
struct Edge{
ll id;
ll op_l;
ll op_r;
ll el;
ll er;
};
vector<Edge> G[N];
const ll M = (ll)1e7;
struct Node{
ll val;
ll lazy;
};
multiset<ll> all_di;
struct Centroid{
set<pii> best;
vector<Node> Tree;
ll CURN;
void init(ll n){
CURN = n;
for(ll i = 0 ; i <= n * 4 + 12; i ++) {
Tree.push_back({0,0});
}
}
void push(ll node, ll cl, ll cr){
Tree[node].val += Tree[node].lazy;
if(cl != cr){
Tree[node * 2].lazy += Tree[node].lazy;
Tree[node * 2 + 1].lazy += Tree[node].lazy;
}
Tree[node].lazy = 0;
}
void upd(ll node, ll cl, ll cr, ll tl, ll tr, ll v){
push(node, cl, cr);
if(cr < tl)
return;
if(cl > tr)
return;
if(cl >= tl && cr <= tr){
Tree[node].lazy += v;
push(node, cl, cr);
return;
}
ll mid = (cl + cr) / 2;
upd(node * 2, cl, mid, tl, tr, v);
upd(node * 2 + 1, mid + 1, cr, tl, tr, v);
Tree[node].val = max(Tree[node * 2].val, Tree[node * 2 + 1].val);
}
ll get(ll node, ll cl, ll cr, ll tl, ll tr){
push(node, cl, cr);
if(cr < tl)
return 0ll;
if(cl > tr)
return 0ll;
if(cl >= tl && cr <= tr){
return Tree[node].val;
}
ll mid = (cl + cr) / 2;
return max(get(node * 2, cl, mid, tl, tr), get(node * 2 + 1, mid + 1, cr, tl, tr));
}
void check(ll mode){
ll sum = 0;
auto it = best.end();
for(ll j = 0 ; j < 2; j ++ ){
if(it != best.begin()){
it -- ;
sum += it->fi;
}
}
if(mode == 1){
all_di.insert(sum);
}
else{
all_di.erase(sum);
}
}
};
Centroid shi[M];
ll idccc = 0;
bool ban[N];
ll subt[N];
void dfs1(ll u, ll par){
subt[u]=1;
for(auto x : T[u]){
if(ban[x.fi] || x.fi == par) continue;
dfs1(x.fi, u);
subt[u] += subt[x.fi];
}
}
ll cc;
ll tin[N];
ll tout[N];
ll las;
ll sz;
void dfs2(ll u, ll par){
tin[u] = cc++;
ll ni, nj;
for(auto x : T[u]){
if(ban[x.fi] || x.fi == par) continue;
dfs2(x.fi, u);
}
tout[u] = cc - 1;
}
void dfs3(ll u, ll par, ll l1, ll r1){
ll ni, nj;
for(auto x : T[u]){
if(ban[x.fi] || x.fi == par) continue;
ni = l1, nj = r1;
if(ni == -1)
ni = tin[x.fi], nj = tout[x.fi];
dfs3(x.fi, u, ni, nj);
shi[las].upd(1, 0, sz - 1, tin[x.fi], tout[x.fi], +ww[x.se]);
G[x.se].push_back({las, tin[x.fi], tout[x.fi], ni, nj});
if(par == -1){
shi[las].best.insert(mp(shi[las].get(1, 0, sz - 1, tin[x.fi], tout[x.fi]), tin[x.fi]));
}
}
}
void decomp(ll node){
dfs1(node, -1);
ll pr = -1;
bool ok = true;
sz = subt[node];
if(sz == 1)
return;
while(ok){
ok = false;
for(auto x : T[node]){
if(ban[x.fi] || x.fi == pr) continue;
if(subt[x.fi] > sz/2){
pr = node;
node = x.fi;
ok = true;
break;
}
}
}
shi[idccc].init(sz);
las=idccc;
idccc ++ ;
cc = 0;
dfs2(node, -1);
dfs3(node, -1, -1, -1);
shi[las].check(1);
ban[node]=true;
for(auto p : T[node]){
if(ban[p.fi]) continue;
decomp(p.fi);
}
}
int main(){
fastIO;
ll lim;
ll n, q;
cin >> n >> q >> lim;
ll u, v;
for(ll i = 0 ; i < n - 1; i ++ ){
cin >> u >> v >> ww[i];
T[u].push_back(mp(v, i));
T[v].push_back(mp(u, i));
}
decomp(1);
ll lasres = 0;
ll id;
ll new_w;
for(ll tt = 0; tt < q; tt ++ ){
cin >> id >> new_w;
id += lasres;
new_w += lasres;
id %= (n - 1);
new_w %= lim;
lasres = 0;
for(auto y : G[id]){
shi[y.id].check(0);
shi[y.id].best.erase(mp(shi[y.id].get(1, 0, shi[y.id].CURN - 1, y.el, y.er), y.el));
shi[y.id].upd(1, 0, shi[y.id].CURN - 1, y.op_l, y.op_r, new_w - ww[id]);
shi[y.id].best.insert(mp(shi[y.id].get(1, 0, shi[y.id].CURN - 1, y.el, y.er), y.el));
shi[y.id].check(1);
}
ww[id] = new_w;
auto gt = all_di.end();
gt -- ;
lasres = *gt;
cout << lasres << "\n";
}
return 0;
}
