#include<cstdio>
#include<cmath>
using namespace std;
int main() {
  //freopen("triangle.in","r",stdin);
  //freopen("triangle.out","w",stdout);
  int a,b; scanf("%d %d",&a,&b);
  if(a==b) printf("%.8lf",sqrt(2*a));
  else printf("%.8lf",sqrt(abs(a*a-b*b)));
  return 0;
}