#include using namespace std; typedef long long ll; typedef vector vi; typedef vector vl; typedef complex P; typedef pair pii; #define REP(i,n) for(ll i=0;i> x; set s; ll y=1; for(ll i=2;i*i<=x;++i){ while(x%i==0){ x/=i; set::iterator iter; if( (iter=s.find(i)) ==s.end()){ y *= i; s.insert(i); }else{ y /= i; s.erase(i); } } } cout << y << endl; return 0; }