#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
#define all(a) a.begin(), a.end()
#define rep(i, a, b) for(ll i = a; i < b; i++)
ld PI = acosl(-1);
ld PI2 = PI * 2;

ld mod_PI2(ld x){
    while(x < 0) x += PI2;
    while(x >= PI2) x -= PI2;
    return x;
}

void solve(){
    ll n,x,y,d,t;
    cin >> n >> x >> y >> d >> t;
    ld first = atan2l(y, x);
    
    vector<ld> th1,th2;

    rep(i, 0, n){
        ll dx,dy;
        cin >> dx >> dy;
        ld th = atan2l(dy, dx);
        ld dth = atan2l(d, sqrtl((dx * dx + dy * dy) - d * d));
        th1.push_back(mod_PI2(th + dth));
        th2.push_back(mod_PI2(th - dth));
    }

    sort(all(th1)); // mx
    sort(all(th2)); // mn

    ld mx, mn;
    rep(i, 0, n){
        if(mod_PI2(th1[i] - th1[(i+1)%n]) < PI) mx = th1[i];
        if(mod_PI2(th2[i] - th2[(i+1)%n]) < PI) mn = th2[(i+1)%n];
    }
    ld ans = 0;

    ld mt = mod_PI2(t);
    ans += (t - mt) / PI2 * mod_PI2(mx - mn);

    mt = mod_PI2(mt - first);
    mx = mod_PI2(mx - first);
    mn = mod_PI2(mn - first);

    if(mx < mn){
        if(mx < mt) ans += mx;
        else ans += mt;
        if(mn < mt) ans += mt - mn;
    }else{
        if(mn < mt){
            ans += min(mx, mt) - mn;
        }
    }

    cout << fixed << setprecision(20) << ans << endl;
}

int main(){
    int t = 1;
    while(t--){
        solve();
    }
}