/in/foo.cc: In function 'int main()':
/in/foo.cc:7:3: warning: statement has no effect [-Wunused-value]
  m<=n;
  ~^~~
/in/foo.cc:8:3: warning: statement has no effect [-Wunused-value]
  n<=300;
  ~^~~~~
/in/foo.cc:9:20: warning: for increment expression has no effect [-Wunused-value]
  for(int i=1;i<=n;i+2)
                   ~^~