/in/foo.cc: In function 'int main()':
/in/foo.cc:8:39: error: 'a' was not declared in this scope
   for(int i=1;i<=e;++i) scanf("%d%d",&a,&b),map[a][b]=true;
                                       ^
/in/foo.cc:8:42: error: 'b' was not declared in this scope
   for(int i=1;i<=e;++i) scanf("%d%d",&a,&b),map[a][b]=true;
                                          ^