#include <bits/stdc++.h>
using namespace std; 
typedef long long i64; 
const int N = 1e5 + 5; 

int n, q, sz[N]; i64 WW; 
int mi[17][N], num, dfn[N], idx[N]; 
vector<pair<int, i64>> G[N]; 
struct Edge {
    int v; i64 w; 
} E[N]; 

i64 C[N]; 
inline void add(int x, i64 k) { for (; x <= n; x += x & -x) C[x] += k; }
inline void add(int l, int r, i64 k) { add(l, k); add(r + 1, -k); }
inline i64 sum(int x) { i64 r = 0; for (; x; x -= x & -x) r += C[x]; return r; }
inline int get(int x, int y) { return dfn[x] < dfn[y] ? x : y; }
void dfs(int x, int ff) {
    mi[0][dfn[x] = ++num] = ff; sz[x] = 1; idx[num] = x; 
    for (auto [y, w] : G[x]) if (y != ff) {
        E[w].v = y; dfs(y, x); 
        add(dfn[y], dfn[y] + sz[y] - 1, E[w].w); 
        sz[x] += sz[y]; 
    }
    cout << x << " " << sz[x] << "\n"; 
}
inline int lca(int u, int v) {
    if (u == v) return u; 
    if ((u = dfn[u]) > (v = dfn[v])) swap(u, v); 
    int k = __lg(v - u++); 
    return get(mi[k][u], mi[k][v - (1 << k) + 1]); 
}
inline i64 dist(int u, int v) {
    return sum(dfn[u]) + sum(dfn[v]) - 2 * sum(dfn[lca(u, v)]); 
}
struct Node {
    int a, b; i64 ans; 
    friend Node operator+ (const Node &a, const Node &b) {
        Node c = (a.ans > b.ans ? a : b); i64 l; 
        if ((l = dist(a.a, b.a)) > c.ans) c.ans = l, c.a = a.a, c.b = b.a; 
        if ((l = dist(a.b, b.a)) > c.ans) c.ans = l, c.a = a.b, c.b = b.a; 
        if ((l = dist(a.a, b.b)) > c.ans) c.ans = l, c.a = a.a, c.b = b.b; 
        if ((l = dist(a.b, b.b)) > c.ans) c.ans = l, c.a = a.b, c.b = b.b; 
        return c; 
    }
} T[N * 4]; 
void build(int o, int l, int r) {
    if (l == r) return T[o] = Node{idx[l], idx[l], 0}, void(); 
    int mid = l + r >> 1; 
    build(o << 1, l, mid); build(o << 1 | 1, mid + 1, r); 
    T[o] = T[o << 1] + T[o << 1 | 1]; 
}
void update(int o, int l, int r, int x, int y) {
    if (x <= l && r <= y) return; 
    int mid = l + r >> 1; 
    if (x <= mid) update(o << 1, l, mid, x, y); 
    if (mid < y) update(o << 1 | 1, mid + 1, r, x, y); 
    T[o] = T[o << 1] + T[o << 1 | 1]; 
}

int main(void) {
    ios::sync_with_stdio(0); cin.tie(0); 
    cin >> n >> q >> WW; 
    for (int i = 1; i < n; ++i) {
        int u, v; i64 w; cin >> u >> v >> w; E[i].w = w; 
        G[u].emplace_back(v, i); G[v].emplace_back(u, i); 
    }
    dfs(1, 0); 
    for (int i = 1; i <= 16; ++i)
        for (int j = 1; j + (1 << i) - 1 <= n; ++j)
            mi[i][j] = get(mi[i - 1][j], mi[i - 1][j + (1 << i - 1)]); 
    build(1, 1, n); 
    // cout << T[1].ans << "\n"; 
    for (int lst = 0; q--; ) {
        int d; i64 e; cin >> d >> e; 
        d = (d + lst) % (n - 1) + 1; e = (e + lst) % WW; 
        // cout << d << " " << e << " UPD\n"; 
        int y = E[d].v; 
        // cout << y << " ETDF\n"; 
        // cout << dfn[y] << " " << dfn[y] + sz[y] - 1 << "\n"; 
        add(dfn[y], dfn[y] + sz[y] - 1, e - E[d].w); E[d].w = e; 
        update(1, 1, n, dfn[y], dfn[y] + sz[y] - 1); 
        cout << (lst = T[1].ans) << "\n"; 
        // cout << T[1].a << " " << T[1].b << "\n";
    }
    return 0;
}