#include<bits/stdc++.h>

using namespace std;

int main(){
    double n,m,ans;
    cin >> n >> m;
    n*=n;
    m*=m;
    if(n==m){
        ans = sqrt(n+m);
    }else if(n>m){
        ans = sqrt(n-m);
    }else{
        ans = sqrt(m-n);
    }
    cout <<ans << endl;
return 0;
}