//Oh? You're Approaching Me? #include <bits/stdc++.h> using namespace std; // //#define int long long typedef long long ll; typedef pair<ll, ll> pll; typedef pair<int, int> pii; // #pragma GCC optimize("O3,unroll-loops") #define migmig ios::sync_with_stdio(false);cin.tie(0);cout.tie(0); #define pb push_back #define F first #define S second #define SZ(x) ll((x).size()) #define all(x) (x).begin(), (x).end() #define cl clear #define endl '\n' #define deb(x) cerr << #x << " = " << x << '\n' #define dokme(x) {cout << x << endl; return;} #define wtf cout << "[ahaaaaaaaaaaaaaaaa]" << endl; const int maxn = 2e6 + 10; const int mod = 998244353; const int inf = 1e9 + 5; const int LOG = 22; const int sq = 502; const int K = 11; #define mid ((l + r) / 2) #define lc (id * 2) #define rc (lc + 1) //g++ main.cpp -o main && main.exe int n, m, lf[maxn], C[maxn], sum; priority_queue<int> pq[maxn]; vector<int> G[maxn]; void dfs(int v) { if (G[v].empty()) { pq[v].push(C[v]); pq[v].push(C[v]); lf[v] = 1; return; } for (int u : G[v]) { dfs(u); if (SZ(pq[u]) > SZ(pq[v])) swap(pq[v], pq[u]); while (!pq[u].empty()) { pq[v].push(pq[u].top()); pq[u].pop(); } lf[v] += lf[u]; } int a = -lf[v]; while (a + SZ(pq[v]) > 1) { pq[v].pop(); } int x = pq[v].top(); pq[v].pop(); int y = pq[v].top(); pq[v].pop(); pq[v].push(C[v] + x); pq[v].push(C[v] + y); } int vc[maxn]; signed main() { cin >> n >> m; C[1] = 0; for (int i = 2; i <= n + m; i++) { int p; cin >> p >> C[i]; G[p].pb(i); sum += C[i]; } dfs(1); while (!pq[1].empty()) { vc[SZ(pq[1])] = pq[1].top(); pq[1].pop(); } vc[0] = 0; int a = -m, i = 1; while (a < 0) { sum += a * (vc[i] - vc[i - 1]); a++; i++; } cout << sum << '\n'; }