#include #include using namespace std; int main(){ int a; int b; cin>> a>> b; cout<<a*b/2;

return 0;

}

参考代码

#include <iostream>
using namespace std;
int main(){

    int a,h;
    double s;
    cin>>a>>h;
    s=a*h/2;
    cout<<s<<endl;
    
    return 0;
}