#pragma GCC optimize ("Ofast") #include using namespace std; void*wmem; char memarr[96000000]; template inline void walloc1d(T **arr, int x, void **mem = &wmem){ static int skip[16] = {0, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1}; (*mem) = (void*)( ((char*)(*mem)) + skip[((unsigned long long)(*mem)) & 15] ); (*arr)=(T*)(*mem); (*mem)=((*arr)+x); } template inline void walloc1d(T **arr, int x1, int x2, void **mem = &wmem){ walloc1d(arr, x2-x1, mem); (*arr) -= x1; } inline int my_getchar_unlocked(){ static char buf[1048576]; static int s = 1048576; static int e = 1048576; if(s == e && e == 1048576){ e = fread_unlocked(buf, 1, 1048576, stdin); s = 0; } if(s == e){ return EOF; } return buf[s++]; } inline void rd(int &x){ int k; int m=0; x=0; for(;;){ k = my_getchar_unlocked(); if(k=='-'){ m=1; break; } if('0'<=k&&k<='9'){ x=k-'0'; break; } } for(;;){ k = my_getchar_unlocked(); if(k<'0'||k>'9'){ break; } x=x*10+k-'0'; } if(m){ x=-x; } } struct MY_WRITER{ char buf[1048576]; int s; int e; MY_WRITER(){ s = 0; e = 1048576; } ~MY_WRITER(){ if(s){ fwrite_unlocked(buf, 1, s, stdout); } } } ; MY_WRITER MY_WRITER_VAR; void my_putchar_unlocked(int a){ if(MY_WRITER_VAR.s == MY_WRITER_VAR.e){ fwrite_unlocked(MY_WRITER_VAR.buf, 1, MY_WRITER_VAR.s, stdout); MY_WRITER_VAR.s = 0; } MY_WRITER_VAR.buf[MY_WRITER_VAR.s++] = a; } inline void wt_L(char a){ my_putchar_unlocked(a); } inline void wt_L(int x){ int s=0; int m=0; char f[10]; if(x<0){ m=1; x=-x; } while(x){ f[s++]=x%10; x/=10; } if(!s){ f[s++]=0; } if(m){ my_putchar_unlocked('-'); } while(s--){ my_putchar_unlocked(f[s]+'0'); } } inline void wt_L(const char c[]){ int i=0; for(i=0;c[i]!='\0';i++){ my_putchar_unlocked(c[i]); } } struct unionFind{ int*d; int N; int M; inline void malloc(const int n){ d = (int*)std::malloc(n*sizeof(int)); M = n; } inline void malloc(const int n, const int fg){ d = (int*)std::malloc(n*sizeof(int)); M = n; if(fg){ init(n); } } inline void free(void){ std::free(d); } inline void walloc(const int n, void **mem=&wmem){ walloc1d(&d, n, mem); M = n; } inline void walloc(const int n, const int fg, void **mem=&wmem){ walloc1d(&d, n, mem); M = n; if(fg){ init(n); } } inline void init(const int n){ int i; N = n; for(i=(0);i<(n);i++){ d[i] = -1; } } inline void init(void){ init(M); } inline int get(int a){ int t = a; int k; while(d[t]>=0){ t=d[t]; } while(d[a]>=0){ k=d[a]; d[a]=t; a=k; } return a; } inline int connect(int a, int b){ if(d[a]>=0){ a=get(a); } if(d[b]>=0){ b=get(b); } if(a==b){ return 0; } if(d[a] < d[b]){ d[a] += d[b]; d[b] = a; } else{ d[b] += d[a]; d[a] = b; } return 1; } inline int operator()(int a){ return get(a); } inline int operator()(int a, int b){ return connect(a,b); } inline int& operator[](const int a){ return d[a]; } inline int size(int a){ a = get(a); return -d[a]; } inline int sizeList(int res[]){ int i; int sz=0; for(i=(0);i<(N);i++){ if(d[i]<0){ res[sz++] = -d[i]; } } return sz; } } ; int N; int M; int A[100000]; int B[100000]; int Y[100000]; int X[100000]; int main(){ int b; wmem = memarr; unionFind uf; rd(N); rd(M); { int Lj4PdHRW; for(Lj4PdHRW=(0);Lj4PdHRW<(M);Lj4PdHRW++){ rd(A[Lj4PdHRW]);A[Lj4PdHRW] += (-1); rd(B[Lj4PdHRW]);B[Lj4PdHRW] += (-1); rd(Y[Lj4PdHRW]); } } uf.walloc(2*N); for(b=(0);b<(30);b++){ int i; uf.init(2*N); for(i=(0);i<(M);i++){ if(((Y[i]) &(1<<(b)))){ uf(A[i], B[i]+N); uf(A[i]+N, B[i]); } else{ uf(A[i], B[i]); uf(A[i]+N, B[i]+N); } } for(i=(0);i<(N);i++){ if(uf(i) == uf(i+N)){ wt_L("-1"); wt_L('\n'); return 0; } } for(i=(0);i<(N);i++){ if(uf(i) >= N){ X[i] |= (1<= N) X[i] |= (1<