#include using namespace std; typedef signed long long ll; #undef _P #define _P(...) (void)printf(__VA_ARGS__) #define FOR(x,to) for(x=0;x<(to);x++) #define FORR(x,arr) for(auto& x:arr) #define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++) #define ALL(a) (a.begin()),(a.end()) #define ZERO(a) memset(a,0,sizeof(a)) #define MINUS(a) memset(a,0xff,sizeof(a)) //------------------------------------------------------- int N,M; vector> E[2][505050]; int st[2][505050]; int W[2][505050]; void solve() { int i,j,k,l,r,x,y; string s; cin>>N>>M; FOR(i,M) { cin>>x>>y>>r; E[0][x].push_back({y,r}); E[1][y].push_back({x,r}); W[0][y]++; W[1][x]++; } queue Q; FOR(i,N) { if(W[0][i]==0) Q.push(i); if(W[1][i]==0) Q.push(i+100000); } while(Q.size()) { int k=Q.front()%100000; int t=Q.front()/100000; Q.pop(); FORR(r,E[t][k]) { st[t][r.first] = max(st[t][r.first],st[t][k]+r.second); if(--W[t][r.first]==0) Q.push(r.first+t*100000); } } int ret=0; FOR(i,N) if(st[0][i]+st[1][i] != st[0][N-1]+st[1][N-1]) ret++; cout<