#include<iostream>
#include<cstdio>
#include<iomanip>
#include<cmath>
using namespace std;
int main(){
    int a,b,buf;
    double ans;
    cin >> a >> b;
    if(a == b) ans = a*sqrt(2.0);
    else{
        ans = sqrt((double)abs(a*a-b*b));
    }
    printf("%.8lf\n",ans);
    return 0;
}