#include<bits/stdc++.h>
#define ll long long
#define pb push_back
#define Mp make_pair
#define e "\n"
#define fl(x,n) for(ll i=x;i<=n;i++)
#define fl2(x,n) for(ll i=x;i>=n;i--)
#define FIO ios_base::sync_with_stdio(false);cin.tie(NULL)
using namespace std;
template<class X>
void temfunc(const X a)
{
    for(auto it=a.begin();it!=a.end();it++)
        cout << *it << " ";
    cout << e;
}


int main()
{
    FIO;
    int a,b,c;
    cin  >> a >> b >> c;
    if(c-b==b-a||c-a==a-b||a-c==c-b||b-c==c-a||a-b==b-c||b-a==a-c)
        cout << "Yes\n";
    else
    {
        cout << "No\n";
    }
    return 0;
}

#include<bits/stdc++.h>
#include<unordered_map>
#define sz(s) (int)s.size()
#define all(s) s.begin(),s.end()
using namespace std;
typedef long long ll;
void fast(){
	std::ios_base::sync_with_stdio(0);
	cin.tie(NULL);
	cout.tie(NULL);
}
void Men7a()
{
	double r, x, y,d;
	int ans;
	cin >> r >> x >> y;
	d = sqrt((x*x)+(y*y));
	if (d - int(d))
	    d++;
	ans = int(d) / int(r);
	if(int(d) % int(r))
		ans++;
	if(d!=r && ans==1)
	    ans++;
	cout << ans << "\n";
}
int main()
{
	fast();
	int test_case = 1;
	//freopen("","r",stdin);
	//cin >> test_case;
	while (test_case--)
		Men7a();
}