/in/foo.cc: In function 'bool CPri(LL)':
/in/foo.cc:9:18: error: 'sqrt' was not declared in this scope
     int Mx=sqrt(x);
                  ^
/in/foo.cc: In function 'void Prep(LL)':
/in/foo.cc:14:24: error: 'sqrt' was not declared in this scope
     Cnt=0;int Mx=sqrt(x);
                        ^