/in/foo.cc: In function 'int main()':
/in/foo.cc:23:5: warning: 'fun' may be used uninitialized in this function [-Wmaybe-uninitialized]
  fun=fun*K;       //乘以天数 
  ~~~^~~~~~
/in/foo.cc:26:5: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
  ans=ans+fun;
  ~~~^~~~~~~~