题解（拿了说一声）

#include<iostream>
using namespace std;
int main(){
int ji=0,tu=0,a,b;
cin >> a >> b;
tu+=(b-a2)/2;
ji+=a-tu;
if(ji<0 || tu<0){
cout << "No";
return 0;
}
if(ji2+tu*4==b ){
cout << "Yes";
}else{
cout << "No" ;
}
return 0;
}