//Make CSP great again
//Vengeance
#include <bits/stdc++.h>
#define TASK "TESTCODE"
using namespace std;
const int N = 1e5;
int n, q;
long long w_mod;
vector<int> adj[N + 1];
int x[N], y[N];
int sz[N + 1], tin[N + 1], tout[N + 1];
int chain[N + 1], nchain, head[N + 1], par[N + 1], bc[N + 1];
long long d[N + 1], w[N];
int dfs_order[N + 1];
struct SegmentTree
{
long long tree[4 * N + 1], lazy[4 * N + 1];
SegmentTree()
{
memset(tree, -0x3f, sizeof(tree));
memset(lazy, 0, sizeof(lazy));
}
void push(int v)
{
long long val = lazy[v];
if (val == 0)
{
return ;
}
lazy[v] = 0;
tree[2 * v] += val;
lazy[2 * v] += val;
tree[2 * v + 1] += val;
lazy[2 * v + 1] += val;
}
void add(int v, int TreeL, int TreeR, int L, int R, long long val)
{
if (L > R)
{
return ;
}
if (TreeL == L && TreeR == R)
{
tree[v] += val;
lazy[v] += val;
return ;
}
push(v);
int mid = (TreeL + TreeR)/2;
add(v * 2, TreeL, mid, L, min(R, mid), val);
add(v * 2 + 1, mid + 1, TreeR, max(L, mid + 1), R, val);
tree[v] = max(tree[2 * v], tree[2 * v + 1]);
}
void add(int L, int R, long long val)
{
add(1, 1, n, L, R, val);
}
long long get(int v, int TreeL, int TreeR, int L, int R)
{
if (L > R)
{
return -1e18;
}
if (TreeL == L && TreeR == R)
{
return tree[v];
}
push(v);
int mid = (TreeL + TreeR)/2;
return max(get(v * 2, TreeL, mid, L, min(R, mid)), get(v * 2 + 1, mid + 1, TreeR, max(L, mid + 1), R));
}
long long get(int L, int R)
{
return get(1, 1, n, L, R);
}
void upd(int v, int TreeL, int TreeR, int pos, long long val)
{
if (TreeL == TreeR)
{
tree[v] = val;
lazy[v] = 0;
return ;
}
int mid = (TreeL + TreeR)/2;
push(v);
if (pos <= mid)
{
upd(v * 2, TreeL, mid, pos, val);
}
else
{
upd(v * 2 + 1, mid + 1, TreeR, pos, val);
}
tree[v] = max(tree[2 * v], tree[2 * v + 1]);
}
void upd(int pos, long long val)
{
upd(1, 1, n, pos, val);
}
int find_max()
{
int v = 1, L = 1, R = n;
while(true)
{
if (L == R)
{
return L;
}
int mid = (L + R)/2;
push(v);
if (tree[2 * v] > tree[2 * v + 1])
{
v = v * 2;
R = mid;
}
else
{
v = v * 2 + 1;
L = mid + 1;
}
}
}
} get_max_d, get_max_hld;
void preDFS(int u, int p)
{
sz[u] = 1;
for (int i : adj[u])
{
int v = x[i] ^ y[i] ^ u;
if (v == p)
{
continue;
}
d[v] = d[u] + w[i];
preDFS(v, u);
sz[u] += sz[v];
}
}
void buildHLD(int u, int p)
{
int bigchild = -1;
static int timer = 0;
tin[u] = ++timer;
dfs_order[timer] = u;
chain[u] = nchain;
if (head[nchain] == 0)
{
head[nchain] = u;
}
for (int i : adj[u])
{
int v = x[i] ^ y[i] ^ u;
if (v == p)
{
continue;
}
if (x[i] == v)
{
swap(x[i], y[i]);
}
if (bigchild == - 1 || sz[v] > sz[bigchild])
{
bigchild = v;
}
}
bc[u] = bigchild;
if (bigchild != -1)
{
par[bigchild] = u;
buildHLD(bigchild, u);
}
for (int i : adj[u])
{
int v = x[i] ^ y[i] ^ u;
if (v == p || v == bigchild)
{
continue;
}
++nchain;
par[v] = u;
buildHLD(v, u);
}
tout[u] = timer;
get_max_d.upd(tin[u], d[u]);
}
long long cal(int u, int except)
{
long long d_u = get_max_d.get(tin[u], tin[u]);
long long d_other = d_u;
if (except != -1)
{
d_other = max(d_other, get_max_d.get(tout[except] + 1, tout[u]));
d_other = max(d_other, get_max_d.get(tin[u], tin[except] - 1));
}
return d_other - 2 * d_u;
}
long long query()
{
long long res = 0;
int p = get_max_d.find_max();
p = dfs_order[p];
int u = p;
long long d_u = get_max_d.get(tin[u], tin[u]);
while(p != 0)
{
int h = head[chain[p]];
if (p != h)
{
res = max(res, d_u + get_max_hld.get(tin[h], tin[par[p]]));
}
p = par[h];
if (p != 0)
{
res = max(res, d_u + cal(p, h));
}
}
return res;
}
void upd(int i, long long nw_w)
{
int u = y[i];
long long dif = nw_w - w[i];
w[i] = nw_w;
get_max_d.add(tin[u], tout[u], dif);
get_max_hld.add(tin[u], tout[u], -dif);
while(true)
{
int h = head[chain[u]];
int p = par[h];
if (p == 0)
{
break;
}
get_max_hld.upd(tin[p], cal(p, bc[p]));
u = p;
}
}
void read()
{
cin >> n >> q >> w_mod;
for (int i = 1; i < n; ++ i)
{
int u, v;
cin >> u >> v >> w[i];
x[i] = u;
y[i] = v;
adj[u].push_back(i);
adj[v].push_back(i);
}
}
void solve()
{
preDFS(1, 0);
buildHLD(1, 0);
for (int u = 1; u <= n; ++ u)
{
get_max_hld.upd(tin[u], cal(u, bc[u]));
}
long long last = 0;
while(q--)
{
long long i, e;
cin >> i >> e;
i = (i + last) % (n - 1);
++i;
e = (e + last) % w_mod;
upd(i, e);
last = query();
cout << last << '\n';
}
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
if (fopen(TASK".INP", "r"))
{
freopen(TASK".INP", "r", stdin);
//freopen(TASK".OUT", "w", stdout);
}
int t = 1;
bool typetest = false;
if (typetest)
{
cin >> t;
}
for (int __ = 1; __ <= t; ++ __)
{
//cout << "Case " << __ << ": ";
read();
solve();
}
}
