#include using namespace std; int main() {

int a,h;

cin>>a>>h; cout<<a*h/2; return 0; }

#include using namespace std; int main(){ int a,b,c,s; cin>>a>>b; c=(a+b)2; s=ab; cout<<c<<' '<<s; return 0; }

#include<cmath>
#include<iostream>
using namespace std;
int main(){
    int a,b,c;
    cin>>a>>b;
    c=2*(a+b);
//FUCK YOU!为什么还要加空格！！！
    cout<<c<<" "<<a*b;
    return 0;
}

#include using namespace std; int main() { int a,b,c,d; cin>>a>>b; c=a*b; d=(a+b)*2; cout<<d<<" "<<c; return 0; }