/in/foo.cc: In function 'double cal(int, int, int)':
/in/foo.cc:110:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
/in/foo.cc: In function 'void solve()':
/in/foo.cc:131:24: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
     printf("%d\n", ans);
                        ^