#define fast ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0)
#include <bits/stdc++.h>
using namespace std;
#define sqr 340
#define mp make_pair
#define mid (l+r)/2
#define le node * 2
#define ri node * 2 + 1
#define pb push_back
#define ppb pop_back
#define fi first
#define se second
#define lb lower_bound
#define ub upper_bound
#define ins insert
#define era erase
#define C continue
#define mem(dp,i) memset(dp,i,sizeof(dp))
#define mset multiset
#define all(x) x.begin(), x.end()
#define gc getchar_unlocked
typedef long long ll;
typedef short int si;
typedef long double ld;
typedef pair<int,int> pi;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<pi> vpi;
typedef vector<pll> vpll;
typedef pair<double,ll>pdi;
const ll inf=1e18;
const ll Mod=1e9+7;
const ld Pi=acos(-1) ;
int n , q , MX ;
vi v [100009] ;
pi edges [100009] ;
map < pi , int > wight ;
void input () {
cin >> n >> q >> MX ;
for ( int i = 0 ; i < n - 1 ; i ++ ) {
int a , b , c ;
scanf ("%d%d%d", &a , &b , &c ) ;
a -- , b -- ;
edges [i] = { a , b } ;
wight [ mp ( a , b ) ] = wight [ mp ( b , a ) ] = c ;
v [a] .pb ( b ) ;
v [b] .pb ( a ) ;
}
}
// Sub1_2
pi Mx ;
int Sub1_2 () {
return ( n <= 5009 && q <= 5009 ) ;
}
void Dfs1 ( int node , int p , int Crnt ) {
Mx = max ( Mx , { Crnt , node } ) ;
for ( auto u : v [node] ) {
if ( u == p ) C ;
Dfs1 ( u , node , Crnt + wight [ mp ( node , u ) ] ) ;
}
}
int BruteForce () {
Mx = { 0 , 0 } ;
Dfs1 ( 0 , 0 , 0 ) ;
Dfs1 ( Mx .se , Mx .se , 0 ) ;
return Mx .fi ;
}
void Sol1_2 () {
int Last = 0 ;
while ( q -- ) {
int id , cost ;
cin >> id >> cost ;
id = ( id + Last ) % ( n - 1 ) ;
cost = ( cost + Last ) % ( MX ) ;
int a = edges [id] .fi , b = edges [id] .se ;
wight [ mp ( a , b ) ] = wight [ mp ( b , a ) ] = cost ;
Last = BruteForce () ;
cout << Last << endl ;
}
}
int main () {
input () ;
if ( Sub1_2 () ) Sol1_2 () ;
// if ( Sub4 () ) Sol4 () ;
// if ( Sub3_5 () ) Sol3_5 () ;
}
