#include<bits/stdc++.h>
#define fi first
#define se second
#define mp make_pair
#define pb push_back
using namespace std;
typedef long long ll;
typedef pair<int, int> ii;
typedef pair<int, ii> iii;
const int N = 1e5 + 5;
const int LOG = 18;
const int INF = 2e9 + 5;
vector<iii> vec;
vector<ii> lst[N];
int dist[N];
void solve_sub2(int n, int q, int w){
int last = 0;
while(q--){
int d, e; cin >> d >> e;
d = (d + last) % (n - 1);
e = (e + last) % w;
vec[d].fi = e;
for(int i = 1; i <= n; ++i)lst[i].clear();
for(int i = 0; i < n - 1; ++i){
lst[vec[i].se.fi].pb(mp(vec[i].se.se, vec[i].fi));
lst[vec[i].se.se].pb(mp(vec[i].se.fi, vec[i].fi));
}
for(int i = 1; i <= n; ++i)dist[i] = INF;
queue<int> q;
q.push(1);
dist[1] = 0;
while(!q.empty()){
int cur = q.front(); q.pop();
for(int i = 0; i < lst[cur].size(); ++i){
int nx = lst[cur][i].fi;
int cs = dist[cur] + lst[cur][i].se;
if(cs < dist[nx]){
dist[nx] = cs;
q.push(nx);
}
}
}
ii maxdist = mp(-1, -1);
for(int i = 1; i <= n; ++i){
maxdist = max(maxdist, mp(dist[i], i));
}
for(int i = 1; i <= n; ++i)dist[i] = INF;
q.push(maxdist.se);
dist[maxdist.se] = 0;
while(!q.empty()){
int cur = q.front(); q.pop();
for(int i = 0; i < lst[cur].size(); ++i){
int nx = lst[cur][i].fi;
int cs = dist[cur] + lst[cur][i].se;
if(cs < dist[nx]){
dist[nx] = cs;
q.push(nx);
}
}
}
int ans = -1;
for(int i = 1; i <= n; ++i){
ans = max(ans, dist[i]);
}
last = ans;
cout << ans << '\n';
}
return;
}
map<int, int> mep;
void solve_sub3(int n, int q, int w){
int last = 0;
while(q--){
int d, e; cin >> d >> e;
d = (d + last) % (n - 1);
e = (e + last) % w;
--mep[vec[d].fi];
if(mep[vec[d].fi] == 0)mep.erase(vec[d].fi);
++mep[e];
vec[d].fi = e;
auto it = mep.end();
--it;
int ans = it->fi;
if(it->se > 1)ans += it->fi;
else{
--it;
ans += it->fi;
}
last = ans;
cout << ans << '\n';
}
return;
}
int par[N];
int depth[N];
int cost[N];
int ar[LOG][N];
int lf[N], rg[N];
struct node{
int mx1, mx2, lz;
};
node st[LOG][4 * N];
node merge(node a, node b){
return {max(a.mx1, b.mx1), max(min(a.mx1, b.mx1), max(a.mx2, b.mx2)), 0};
}
void build(int idx, int l, int r, int lg){
if(l == r){
st[lg][l] = {ar[lg][l], -1, 0};
return;
}
int m = (l + r)/2;
build(idx * 2, l, m, lg);
build(idx * 2 + 1, m + 1, r, lg);
st[lg][idx] = merge(st[lg][idx * 2], st[lg][idx * 2 + 1]);
return;
}
void apply(int idx, int l, int r, int v, int lg){
st[lg][idx].mx1 += v;
st[lg][idx].mx2 += v;
st[lg][idx].lz += v;
return;
}
void pushdown(int idx, int l, int r, int lg){
if(st[lg][idx].lz == 0)return;
int m = (l + r)/2;
apply(idx * 2, l, m, st[lg][idx].lz, lg);
apply(idx * 2 + 1, m + 1, r, st[lg][idx].lz, lg);
st[lg][idx].lz = 0;
return;
}
void upd(int idx, int l, int r, int x, int y, int v, int lg){
if(l > y || r < x)return;
if(l >= x && r <= y){
apply(idx, l, r, v, lg);
return;
}
pushdown(idx, l, r, lg);
int m = (l + r)/2;
upd(idx * 2, l, m, x, y, v, lg);
upd(idx * 2 + 1, m + 1, r, x, y, v, lg);
st[lg][idx] = merge(st[lg][idx * 2], st[lg][idx * 2 + 1]);
return;
}
node get(int idx, int l, int r, int x, int y, int lg){
if(l > y || r < x)return {-1, -1, 0};
if(l >= x && r <= y)return st[lg][idx];
pushdown(idx, l, r, lg);
int m = (l + r)/2;
return merge(get(idx * 2, l, m, x, y, lg), get(idx * 2 + 1, m + 1, r, x, y, lg));
}
ii dfs(int idx, int p){
par[idx] = p;
ii res = mp(INF, 0);
for(int i = 0; i < lst[idx].size(); ++i){
int nx = lst[idx][i].fi;
if(nx == p)continue;
cost[nx] = lst[idx][i].se;
depth[nx] = depth[idx] + 1;
ii cur = dfs(nx, idx);
res.fi = min(res.fi, cur.fi);
res.se = max(res.se, cur.se);
}
lf[idx] = res.fi; rg[idx] = res.se;
return res;
}
void build_ar(int l, int r){
for(int i = l; i <= r; ++i){
int idx = i;
int sum_cost = 0;
while(par[idx] != -1){
sum_cost += cost[idx];
idx = par[idx];
ar[depth[idx]][i] = sum_cost;
}
}
return;
}
node rs[N];
int main(){
ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
int n, q, w; cin >> n >> q >> w;
bool sub3 = true;
for(int i = 0; i < n - 1; ++i){
int a, b, c; cin >> a >> b >> c;
lst[a].pb(mp(b, c));
lst[b].pb(mp(a, c));
vec.pb(mp(c, mp(a, b)));
++mep[c];
if(a != 1 && b != 1)sub3 = false;
}
if(n <= 5000 && q <= 5000){
solve_sub2(n, q, w);
return 0;
}
if(sub3){
solve_sub3(n, q, w);
return 0;
}
mep.clear();
dfs(1, -1);
int id_l = 0;
for(int i = 1; i <= n; ++i){
if(lst[i].size() == 1){
id_l = i;
break;
}
}
build_ar(id_l, n);
for(int i = 0; i < LOG; ++i)build(1, 1, n, i);
for(int i = 1; i < id_l; ++i){
rs[i] = get(1, 1, n, lf[i], rg[i], depth[i]);
mep[rs[i].mx1 + rs[i].mx2]++;
}
int last = 0;
while(q--){
int d, e; cin >> d >> e;
d = (d + last) % (n - 1);
e = (e + last) % w;
int x = vec[d].se.fi, y = vec[d].se.se;
if(depth[x] < depth[y])swap(x, y);
int idx = x;
while(par[idx] != -1){
idx = par[idx];
int last_sum = rs[idx].mx1 + rs[idx].mx2;
mep[last_sum]--;
upd(1, 1, n, lf[x], rg[x], e - cost[x], depth[idx]);
rs[idx] = get(1, 1, n, lf[idx], rg[idx], depth[idx]);
mep[rs[idx].mx1 + rs[idx].mx2]++;
}
cost[x] = e;
vec[d].fi = e;
auto it = mep.end();
--it;
while(it->se == 0){
mep.erase(it->fi);
--it;
}
int ans = it->fi;
if(it->se > 1){
ans += it->fi;
}else{
while(it->se == 0){
mep.erase(it->fi);
--it;
}
--it;
ans += it->fi;
}
last = ans;
cout << ans << '\n';
}
return 0;
}
