#include <algorithm>
#include <bitset>
#include <climits>
#include <cmath>
#include <cstdio>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <vector>

#define MOD 1000000007
#define MOD2 998244353
#define int long long
#define double long double
#define EPS 1e-9
//#define PI 3.14159265358979

#define rep(i, n) for (int i = 0; i < (int)(n); i++)

using namespace std;

template < typename T >
ostream &operator<<(ostream &os, const vector< T > &A) {
	for (int i = 0; i < A.size(); i++)
		os << A[i] << " ";
	os << endl;
	return os;
}
template <>
ostream &operator<<(ostream &os, const vector< vector< int > > &A) {
	int N = A.size();
	for (int i = 0; i < N; i++) {
		for (int j = 0; j < A[i].size(); j++)
			os << A[i][j] << " ";
		os << endl;
	}
	return os;
}

typedef pair< int, int > pii;
typedef long long ll;

struct edge {
	int from, to, d, c;
	edge(int _from = 0, int _to = 0, int _d = 0, int _c = 0) {
		from = _from;
		to = _to;
		d = _d;
		c = _c;
	}
	bool operator<(const edge &rhs) const {
		return (d == rhs.d) ? (c < rhs.c) : (d < rhs.d);
	}
};
struct aabb {
	int x1, y1, x2, y2;
	aabb(int x1, int y1, int x2, int y2) : x1(x1), y1(y1), x2(x2), y2(y2) {}
};

typedef vector< edge > edges;
typedef vector< edges > graph;
struct flow {
	int to, cap, rev, cost;
	flow(int to = 0, int cap = 0, int rev = 0, int cost = 0) : to(to), cap(cap), rev(rev), cost(cost) {}
};
typedef vector< vector< flow > > flows;

const int di[4] = {0, -1, 0, 1};
const int dj[4] = {-1, 0, 1, 0};
const int ci[5] = {0, 0, -1, 0, 1};
const int cj[5] = {0, -1, 0, 1, 0};
const ll LINF = LLONG_MAX / 2;
const int INF = INT_MAX / 2;
const double PI = acos(-1);

int pow2(int n) { return 1LL << n; }
template < typename T, typename U >
bool chmin(T &x, const U &y) {
	if (x > y) {
		x = y;
		return true;
	}
	return false;
}
template < typename T, typename U >
bool chmax(T &x, const U &y) {
	if (x < y) {
		x = y;
		return true;
	}
	return false;
}

template < typename A, size_t N, typename T >
void Fill(A (&array)[N], const T &val) {
	fill((T *)array, (T *)(array + N), val);
}
struct initializer {
	initializer() {
		cout << fixed << setprecision(20);
	}
};
initializer _____;
template < class Monoid, class Action >
struct LSegT {
	int N;
	vector< Monoid > node;
	vector< Action > lazy;
	Monoid UNITY_MONOID; //to be set------------------------
	Action UNITY_ACTION; //to be set------------------------
	Monoid merge(const Monoid &l, const Monoid &r) {
		//to be set---------------------------------
		//return l+r;
		return;
	}
	LSegT(vector< Monoid > &A) {
		int sz = A.size();
		N = 1;
		while (N < sz)
			N <<= 1;
		node.resize(2 * N - 1);
		lazy.resize(2 * N - 1, 0);
		rep(i, sz) node[i + N - 1] = A[i];
		for (int i = N - 2; i >= 0; i--)
			node[i] = merge(node[i * 2 + 1], node[i * 2 + 2]);
	}
	void reflect(int k, int l, int r) {
		//to be set----------------------------------------
		//node[k]+=lazy[k];
	}
	void add(Action &d, const Action &e) {
		//to be set---------------------------------------
		//d+=e;
	}
	void eval(int k, int l, int r) {
		if (lazy[k] != UNITY_ACTION) {
			reflect(k, l, r);
			if (r - l > 1) {

				add(lazy[2 * k + 1], lazy[k]);
				add(lazy[2 * k + 2], lazy[k]);
				//if p,use this
				//add(lazy[2 * k + 1], lazy[k] / 2);
				//add(lazy[2 * k + 2], lazy[k] / 2);
			}
			lazy[k] = UNITY_ACTION;
		}
	}
	void set(int a, int b, Action x, int k = 0, int l = 0, int r = -1) {
		if (r < 0)
			r = N;
		if (b <= l || r <= a)
			eval(k, l, r);
		else if (a <= l && r <= b) {
			add(lazy[k], x);
			//if p,use this
			//add(lazy[k] , (r - l) * x);
			eval(k, l, r);
		} else {
			eval(k, l, r);
			set(a, b, x, 2 * k + 1, l, (l + r) / 2);
			set(a, b, x, 2 * k + 2, (l + r) / 2, r);
			node[k] = merge(node[2 * k + 1], node[2 * k + 2]);
		}
	}
	Monoid get(int a, int b, int k = 0, int l = 0, int r = -1) {
		if (r < 0)
			r = N;
		if (b <= l || r <= a)
			return UNITY_MONOID;
		eval(k, l, r);
		if (a <= l && r <= b)
			return node[k];
		Monoid vl = get(a, b, 2 * k + 1, l, (l + r) / 2);
		Monoid vr = get(a, b, 2 * k + 2, (l + r) / 2, r);
		return node[k] = merge(vl, vr);
	}
};
template < class Monoid >
struct SegT {
	//to be set--------------------------------------------------
	const static Monoid UNITY = LINF; //UNITY=0
	Monoid merge(const Monoid &a, const Monoid &b) {
		return min(a, b); //a+b;
	}
	//kokomade----------------------------------------------------
	vector< Monoid > container;
	int n;
	void update(int i, Monoid x) {
		int ii = i + n - 1;
		container[ii] = x;
		while (ii > 0) {
			ii = (ii - 1) / 2;
			container[ii] = merge(container[2 * ii + 1], container[2 * ii + 2]);
		}
	}
	Monoid get(int l, int r, int l2 = 0, int r2 = -1, int k = 0) {
		if (r2 == -1)
			r2 = n;
		if (r2 <= l || r <= l2)
			return UNITY;

		if (l <= l2 && r2 <= r)
			return container[k];
		ll vl = get(l, r, l2, (l2 + r2) / 2, 2 * k + 1);
		ll vr = get(l, r, (l2 + r2) / 2, r2, 2 * k + 2);

		return merge(vl, vr);
	}
	void init(vector< Monoid > &A) {
		n = 1;
		while (n < A.size())
			n <<= 1;
		container = vector< Monoid >(2 * n - 1, 0);
		for (int i = 0; i < A.size(); i++)
			update(i, A[i]);
	}
	SegT(vector< Monoid > &A) {
		init(A);
	}
	SegT(int _n) {
		vector< Monoid > A(_n, UNITY);
		init(A);
	}
};
int N, M, K, T, Q, H, W;
signed main() {
	cin >> H >> W;
	vector< int > A(H), B(H);
	rep(i, H) {
		cin >> A[i] >> B[i];
		--A[i];
		--B[i];
	}
	vector< int > tmp(W, 0);
	SegT< int > sgt(tmp);
	map< int, int > m;
	rep(i, W) m[i] = i;
	vector< int > ans(H, LINF);
	rep(i, H) {
		auto it = m.lower_bound(A[i]);
		int r = -1;
		while (it != m.end() && it->first <= B[i]) {
			sgt.update(it->second, LINF);
			chmax(r, it->second);
			//cerr << it->second << " " << it->first << endl;
			it = m.erase(it);
		}
		//cerr << r << endl;
		if (r != -1 && B[i] < W - 1) {
			chmax(m[B[i] + 1], r);
			sgt.update(m[B[i] + 1], B[i] - m[B[i] + 1] + 1);
		}
		//cerr << sgt.get(0, W) << endl;
		//rep(j, W) cerr << sgt.get(j, j + 1) << " ";
		//cout << endl;
		ans[i] = sgt.get(0, W) + i + 1;
	}
	rep(i, H) {
		if (ans[i] >= LINF)
			ans[i] = -1;
		cout << ans[i] << endl;
	}
	return 0;
}

Measured memory_bytes: 26212