#include <stdio.h>
#include <math.h>

int main() {
    long long R, X, Y;
    scanf("%lld %lld %lld", &R, &X, &Y);
    int ans;
    if (X * X + Y * Y < R * R) {
        ans = 2;
    }
    else {
        double dis = sqrt((1.0 * X * X + 1.0 * Y * Y) / (1.0 * R * R));
        ans = ceil(dis);
    }
    printf("%d\n", ans);
    return 0;
}
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define endl "\n"
ll mod=1000000007;
#define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int main()
{
    IOS;
    #ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    #endif

    //ll t;cin>>t;while(t--)
    {
        ll a,b,c,d,i,j,k,l,m,n,sum=0,temp=0,f=0,cnt=0;
        double x1,y1,x2,y2;
        cin>>x1>>y1>>x2>>y2;
        double ans=((x2*y1)+(x1*y2))/(y1+y2);
        cout<<fixed<<setprecision(7)<<ans<<endl;


    }
}
