Avin has two integers a, b (1 ≤ a, b ≤ 1, 000).
Given x = a + b and y = a - b, can you calculate ab?
Input
The first line contains two integers x, y.
Output
Print the result of ab.
Sample Input
4 2
Sample Output
3
#include<iostream>
using namespace std;
int main()
{
double x,y;
scanf("%lf%lf",&x,&y);
double xx=(x+y)/2.0;double yy=(x-y)/2.0;
cout<<xx*yy<<endl;
//printf("%d\n",xx*yy);
return 0;
}