#include<bits/stdc++.h>
#define int long long
#define fr(i,j,k) for(register int i=j;i<=k;++i)
#define rf(i,j,k) for(register int i=j;i>=k;--i)
#define foredge(i,j) for(register int i=head[j];i;i=e[i].nxt)
#define pb push_back
#define Times printf("Time:%.3lf\n",clock()/CLOCKS_PER_SEC)
using namespace std;
inline int read(){
	int x=0;
	bool f=0;
	char c=getchar();
	while(!isdigit(c)) f|=(c=='-'),c=getchar();
	while(isdigit(c)) x=(x<<3)+(x<<1)+(c^48),c=getchar();
	return f?-x:x;
}
inline void write(int x){
    if(x<0){putchar('-');x=-x;}
    if(x>9)write(x/10);
    putchar(x%10+'0');
}
inline void writeln(int x){write(x); puts("");}
inline void writepl(int x){write(x); putchar(' ');}
mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
inline int randfind(int l,int r){return rnd()%(r-l+1)+l;}
int n;
const int Maxn=2e4+10;
struct node{
    int nxt,to,d;
}e[Maxn<<1];
int head[Maxn],cnt;
inline void add(int u,int v,int w){
    ++cnt;
    e[cnt].nxt=head[u];
    head[u]=cnt;
    e[cnt].to=v;
    e[cnt].d=w;
}
int f[Maxn][2020];
inline void clear(){
    cnt=0;
    fr(i,1,n) head[i]=0;
    fr(i,1,n) fr(j,0,2018) f[i][j]=0;
}
int s[Maxn];
const int mod=2019;
int ans;
inline void dfs(int x,int fa){
    for(register int i=head[x];i;i=e[i].nxt){
        int y;y=e[i].to;
        if(y==fa) continue;
        s[y]=(s[x]+e[i].d)%mod;
        dfs(y,x);
    }
}
inline void dfs1(int x,int fa){
    f[x][s[x]]=1;
    for(register int i=head[x];i;i=e[i].nxt){
        int y;y=e[i].to;
        if(y==fa) continue;
        dfs1(y,x);
        fr(i,0,mod-1) ans+=f[x][i]*f[y][(mod-i+s[x]*2)%mod];
        fr(i,0,mod-1) f[x][i]+=f[y][i];
    }
}
inline void work(){
    clear();
    ans=0;
    fr(i,1,n-1){
        int x,y,z;
        x=read();y=read();z=read();
        add(x,y,z);add(y,x,z);
    }
    dfs(1,0);dfs1(1,0);
    // fr(i,1,n) cout<<i<<' '<<s[i]<<endl;
    writeln(ans);
}
inline void init(){
	while(cin>>n) work();
}
signed main(){
	// freopen("input.in","r",stdin);
	// freopen("output.out","w",stdout);
    init();
    // printf("\nTIME:%.3lf",(double)clock()/CLOCKS_PER_SEC);
	return 0;
}