View Compilation Error

0_0_39425270_13590.cpp: In function 'int main()':
0_0_39425270_13590.cpp:35:82: error: void value not ignored as it ought to be
   35 |                 for(int i=1,x,y,w;i<=m;++i) scanf("%d %d %d",&x,&y,&w), ans+=join(x,y,w);
      |                                                                              ~~~~^~~~~~~