#include <bits/stdc++.h>
using namespace std;
#define POPCOUNT(n) (__builtin_popcountll((n)))
#define CLZ(n) (__builtin_clzll((n)))
#define CTZ(n) (__builtin_ctzll((n)))
#define LOG(n) (63 - __builtin_clzll((n)))
#define BIT(n, i) (((n) >> (i)) & 1ll)
#define MASK(i) (1ll << (i))
#define FLIP(n, i) ((n) ^ (1ll << (i)))
#define ON(n, i) ((n) | MASK(i))
#define OFF(n, i) ((n) & ~MASK(i))
#define Int __int128
#define fi first
#define se second
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<long long, long long> pll;
typedef pair<long long, int> pli;
typedef pair<int, long long> pil;
typedef vector<pair<int, int>> vii;
typedef vector<pair<long long, long long>> vll;
typedef vector<pair<long long, int>> vli;
typedef vector<pair<int, long long>> vil;
template <class T1, class T2> bool maximize(T1 &x, T2 y) {
if (x < y) {
x = y;
return true;
}
return false;
}
template <class T1, class T2> bool minimize(T1 &x, T2 y) {
if (x > y) {
x = y;
return true;
}
return false;
}
template <class T> void remove_duplicate(vector<T> &ve) {
sort (ve.begin(), ve.end());
ve.resize(unique(ve.begin(), ve.end()) - ve.begin());
}
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
long long random(long long l, long long r) {
return uniform_int_distribution<long long>(l, r)(rng);
}
unsigned long long random(unsigned long long l, unsigned long long r) {
return uniform_int_distribution<unsigned long long>(l, r)(rng);
}
template <class T> T random(T r) {
return rng() % r;
}
const int N = 1e5 + 5;
const int MOD = 1e9 + 7;
const int inf = 1e9;
const long long INF = 1e18;
int n, m, k;
pii a[N];
vector<int> adj[N];
struct SlopeTrick {
map<int, ll> slope;
ll rightSlope, value;
SlopeTrick() {
slope.clear();
rightSlope = value = 0;
}
int size() {
return slope.size();
}
bool empty() {
return size() == 0;
}
void add(ll x, ll y) {
slope[x] += y;
}
} T[N];
void dfs(int u) {
if (a[u] != make_pair(0, 0)) {
T[u].slope[a[u].fi] = a[u].se;
T[u].slope[a[u].fi + 1] = -a[u].se;
T[u].rightSlope = 0;
T[u].value = 0;
}
for (auto v : adj[u]) {
dfs(v);
if (T[u].size() < T[v].size()) swap(T[u], T[v]);
if (!T[u].empty() && !T[v].empty()) {
ll x = T[u].slope.rbegin()->fi, y = T[v].slope.rbegin()->fi;
if (x < y) {
T[u].value += T[u].rightSlope * (y - x);
}
else {
T[v].value += T[v].rightSlope * (x - y);
}
T[u].rightSlope += T[v].rightSlope;
T[u].value += T[v].value;
// cerr << "merge " << u << ' ' << v << ' ' << T[u].value << '\n';
for (auto &x : T[v].slope) T[u].add(x.fi, x.se);
}
}
while (!T[u].empty() && T[u].rightSlope - T[u].slope.rbegin()->se > 0) {
auto it = T[u].slope.rbegin();
T[u].value += (T[u].rightSlope - it->se) * (it->fi - prev(it)->fi);
T[u].rightSlope -= it->se, T[u].slope.erase(it->fi);
}
T[u].rightSlope = 0;
// cerr << "value " << u << ' ' << T[u].value << ' ' << T[u].rightSlope << '\n';
// for (auto &x : T[u].slope) cerr << x.fi << ' ' << x.se << '\n';
// cerr << '\n';
}
signed main() {
ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
cin >> n >> m >> k;
for (int i = 2; i <= n; ++i) {
int p; cin >> p;
adj[p].emplace_back(i);
}
for (int i = 1; i <= m; ++i) {
int v, d, w; cin >> v >> d >> w;
a[v] = make_pair(d, w);
}
dfs(1);
cout << T[1].value;
return 0;
}
