#include <bits/stdc++.h>
using namespace std;
typedef long long int lli;
typedef pair<int,int> pii;
const int MAXN = 100010;
class SegmentTree
{
public:
int getLeft(int node) { return 2*node; }
int getRight(int node) { return 2*node + 1; }
void refresh(int node, int l, int r)
{
if( lazy[node] == 0 ) return;
lli lz = lazy[node];
lazy[node] = 0;
mx[node] += lz;
if( l == r ) return;
lazy[ getLeft(node) ] += lz;
lazy[ getRight(node) ] += lz;
}
void update(int node, int l, int r, int i, int j, lli v)
{
refresh( node , l , r );
if( j < l || r < i ) return;
if( i <= l && r <= j )
{
lazy[node] += v;
refresh( node , l , r );
return;
}
int m = ( l + r )/2;
update( getLeft(node) , l , m , i , j , v );
update( getRight(node) , m + 1 , r , i , j , v );
mx[node] = max( mx[ getLeft(node) ] , mx[ getRight(node) ] );
}
lli query(int node, int l, int r, int i, int j)
{
refresh( node , l , r );
if( j < l || r < i ) return 0;
if( i <= l && r <= j ) return mx[node];
int m = ( l + r )/2;
lli mxLeft = query( getLeft(node) , l , m , i , j );
lli mxRight = query( getRight(node) , m + 1 , r , i , j );
return max( mxLeft , mxRight );
}
SegmentTree()
{
memset( mx , 0 , sizeof(mx) );
memset( lazy , 0 , sizeof(lazy) );
}
private:
lli mx[4*MAXN];
lli lazy[4*MAXN];
};
int n, q;
int curTime;
int tin[MAXN];
int tout[MAXN];
int node[MAXN];
int indSubtree[MAXN];
lli maxW;
lli lastAns;
lli value[MAXN];
lli weight[MAXN];
pii edge[MAXN];
vector< int > adj[MAXN];
vector< int > indEdge[MAXN];
multiset< lli > paths;
SegmentTree SEG;
void DFS(int cur, int p)
{
tin[cur] = ++curTime;
node[curTime] = cur;
for(int i = 0 ; i < adj[cur].size() ; i++)
{
int viz = adj[cur][i];
if( viz != p )
DFS( viz , cur );
}
tout[cur] = curTime;
}
lli diameter()
{
lli sum = 0;
auto it = paths.end();
it--;
sum += *it;
it--;
sum += *it;
return sum;
}
int main()
{
scanf("%d %d %lld",&n,&q,&maxW);
for(int i = 1 ; i < n ; i++)
{
int U, V;
lli W;
scanf("%d %d %lld",&U,&V,&W);
adj[U].push_back( V );
adj[V].push_back( U );
indEdge[U].push_back( i );
indEdge[V].push_back( i );
weight[i] = W;
edge[i] = { U , V };
}
DFS( 1 , 1 );
for(int i = 1 ; i < n ; i++)
{
int U = edge[i].first;
int V = edge[i].second;
if( tin[U] > tin[V] ) swap( U , V );
SEG.update( 1 , 1 , n , tin[V] , tout[V] , weight[i] );
}
paths.insert( 0 );
for(int i = 0 ; i < adj[1].size() ; i++)
{
int viz = adj[1][i];
value[i] = SEG.query( 1 , 1 , n , tin[viz] , tout[viz] );
paths.insert( value[i] );
for(int j = tin[viz] ; j <= tout[viz] ; j++)
indSubtree[ node[j] ] = i;
}
for(int i = 1 ; i <= q ; i++)
{
lli d, e;
scanf("%lld %lld",&d,&e);
d = ( d + lastAns )%( n - 1 ) + 1;
e = ( e + lastAns )%maxW;
int U = edge[d].first;
int V = edge[d].second;
if( tin[U] > tin[V] ) swap( U , V );
SEG.update( 1 , 1 , n , tin[V] , tout[V] , -weight[d] );
weight[d] = e;
SEG.update( 1 , 1 , n , tin[V] , tout[V] , weight[d] );
int curInd = indSubtree[V];
paths.erase( paths.find( value[curInd] ) );
value[curInd] = SEG.query( 1 , 1 , n , tin[ adj[1][curInd] ] , tout[ adj[1][curInd] ] );
paths.insert( value[curInd] );
lastAns = diameter();
printf("%lld\n",lastAns);
}
}
