//Never stop trying
#include <bits/stdc++.h>
using namespace std;
#define boost ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)
typedef string str;
typedef long long ll;
#define int ll
typedef double db;
typedef long double ld;
typedef pair<int, int> pi;
#define fi first
#define se second
typedef vector<int> vi;
typedef vector<pi> vpi;
typedef vector<str> vs;
typedef vector<ld> vd;
#define pb push_back
#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define endl "\n"
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
const int MOD = 1e9 + 7; //998244353
const ll INF = 1e18;
const int MX = 1e5 + 10;
const int nx[4] = {0, 0, 1, -1}, ny[4] = {1, -1, 0, 0}; //right left down up
template<class T> using V = vector<T>;
template<class T> bool ckmin(T& a, const T& b) { return a > b ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; }
ll cdiv(ll a, ll b) { return a / b + ((a ^ b) > 0 && a % b); } // divide a by b rounded up
constexpr int log2(int x) { return 31 - __builtin_clz(x); } // floor(log2(x))
#define dbg(x) cerr << " - " << #x << " : " << x << endl;
#define dbgs(x,y) cerr << " - " << #x << " : " << x << " / " << #y << " : " << y << endl;
#define dbgv(v) cerr << " - " << #v << " : " << endl << "[ "; for(auto it : v) cerr << it << ' '; cerr << ']' << endl;
void IO() {
#ifndef ONLINE_JUDGE
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
}
int N,Q,W;
vi adj[MX];
vpi edges;
unordered_map<int,int> ed[MX];
bool sub3(){
FOR(i,0,N-1){
if(edges[i].fi!=1 && edges[i].se!=-1) return false;
}
return true;
}
int dist[MX];
void dfs(int u, int p){
for(auto v: adj[u]) if(v!=p){
dist[v]=dist[u]+ed[u][v];
dfs(v,u);
}
}
int solve(){
FOR(i,1,N+1) dist[i]=-INF;
dist[1]=0;
dfs(1,1);
int d=0,u=1;
FOR(i,2,N+1)
if(dist[i]>d){
d=dist[i];
u=i;
}
FOR(i,1,N+1) dist[i]=-INF;
dist[u]=0;
dfs(u,u);
d=0;
FOR(i,1,N+1)
if(dist[i]>d) d=dist[i];
return d;
}
int32_t main() {
boost;
cin>>N>>Q>>W;
FOR(i,0,N-1){
int u,v,w; cin>>u>>v>>w;
edges.pb({u,v});
adj[u].pb(v); adj[v].pb(u);
ed[u][v]=w; ed[v][u]=w;
}
if(sub3()){
multiset<int> s;
int w[N];
FOR(i,0,N-1){
w[i]=ed[edges[i].fi][edges[i].se];
s.insert(w[i]);
}
int last=0;
while(Q--){
int i,nw; cin>>i>>nw;
i=(i+last)%(N-1);
nw=(nw+last)%W;
int u=edges[i].fi,v=edges[i].se;
s.erase(s.find(w[i]));
w[i]=nw;
s.insert(w[i]);
auto it=s.end(); it--;
int res=(*it);
if(it!=s.begin()){
it--; res+=(*it);
}
cout << res << endl;
last=res;
}
}
else{
int last=0;
while(Q--){
int i,w; cin>>i>>w;
i=(i+last)%(N-1);
w=(w+last)%W;
int u=edges[i].fi,v=edges[i].se;
ed[u][v]=ed[v][u]=w;
int res=solve();
cout << res << endl;
last=res;
}
}
return 0;
}
/* Careful!!!
.Array bounds
.Infinite loops
.Uninitialized variables / empty containers
.Order of input
Some insights:
.Binary search
.Graph representation
.Write brute force code
.Change your approach
*/
