#include <bits/stdc++.h>
using namespace std;
#define rep(i,l,r) for (int i = (l); i <= (r); i++)
#define per(i,r,l) for (int i = (r); i >= (l); i--)
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
#define maxn(a, b) a = max(a, b)
#define minn(a, b) a = min(a, b)
typedef vector<int> VI;
typedef long long ll;
typedef pair<int,int> PII;
typedef double db;
const ll mod = 998244353;
mt19937 gen(random_device{}());
ll rp(ll a,ll b) {ll res=1%mod;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;}

int main() {
    int q, w;
    scanf("%d%d", &q, &w);
    set<PII> st;
    multiset<int> X, Y;
    while (q--) {
        int x, y;
        scanf("%d%d", &x, &y);
        if (st.count(mp(x, y))) {
            X.erase(X.find(y - x));
            Y.erase(Y.find(y + x));
            st.erase(mp(x, y));
        } else {
            X.insert(y - x);
            Y.insert(y + x);
            st.insert(mp(x, y));
        }

        db ans = 0;
        if (!st.empty()) {
            int mx = *X.rbegin();
            int my = *Y.rbegin();
            // (y - x = mx && y + x == my)
            db xx = (my - mx) / 2.0;
            db yy = (my + mx) / 2.0;
            // printf("%d %d %d %d\n", x, y, mx, my);
            ans += sqrtl(min(xx, yy) * 1ll * min(xx, yy) * 2);
            ans += sqrtl(min(yy, w - xx) * 1ll * min(yy, w - xx) * 2);
        }
        printf("%.6lf\n", ans);
    }
    return 0;
}