#include <bits/stdc++.h>
using namespace std;const int INF = 0x3f3f3f3f;
const int maxn = 1000;struct Edge
{int from,to;int dist;
};struct BellmanFord
{int n,m;vector<Edge> edges;vector<int> G[maxn];bool inq[maxn];int d[maxn];int p[maxn];int cnt[maxn];void init(int n){this->n = n;for(int i=0; i<n; i++) G[i].clear();edges.clear();}void AddEdge(int from,int to,int dist){edges.push_back((Edge){from,to,dist});m = edges.size();G[from].push_back(m-1);}bool negativeCycle(int s){queue<int> Q;memset(inq,0,sizeof(inq));memset(cnt,0,sizeof(cnt));for(int i=0; i<n; i++){d[i] = INF;}d[s] = 0;inq[s] = true;Q.push(s);while(!Q.empty()){int u = Q.front();Q.pop();inq[u] = false;for(int i=0; i<G[u].size(); i++){Edge& e = edges[G[u][i]];if(d[u]<INF&&d[e.to]>d[u]+e.dist){d[e.to] = d[u] + e.dist;p[e.to] = G[u][i];if(!inq[e.to]){Q.push(e.to);inq[e.to] = true;if(++cnt[e.to]>n)return false;}}}}return true;}};struct BellmanFord
{int n,m;vector<Edge> edges;vector<int> G[maxn];bool inq[maxn];int d[maxn];int p[maxn];int cnt[maxn];void init(int n){this->n = n;for(int i=0; i<n; i++) G[i].clear();edges.clear();}void AddEdge(int from,int to,int dist){edges.push_back((Edge){from,to,dist});m = edges.size();G[from].push_back(m-1);}bool negativeCycle(){queue<int> Q;memset(inq,0,sizeof(inq));memset(cnt,0,sizeof(cnt));for(int i=0; i<n; i++){d[i] = 0;inq[0] = true;Q.push(i);}while(!Q.empty()){int u = Q.front();Q.pop();inq[u] = false;for(int i=0; i<G[u].size(); i++){Edge& e = edges[G[u][i]];if(d[e.to]>d[u]+e.dist){d[e.to] = d[u] + e.dist;p[e.to] = G[u][i];if(!inq[e.to]) {Q.push(e.to);inq[e.to] = true;if(++cnt[e.to]>n)return true;}}}}return false;}};