### BUGGY CODE ###

import sys
import random


class RandomizedBinarySearchTree:
    def __init__(self, n):
        n += 10
        self.n = n
        self.children = [[0] * n, [0] * n]
        self.values = [0] * n
        self.counts = [0] * n
        self.indices = list(range(n - 2, -1, -1))
        self.root = -1

    def merge(self, left_root, right_root):
        children = self.children
        counts = self.counts
        li = left_root
        ri = right_root
        stack = []
        while li != -1 and ri != -1:
            if random.randrange(counts[li] + counts[ri]) < counts[li]:
                stack.append((li, 1))
                li = children[1][li]
            else:
                stack.append((ri, 0))
                ri = children[0][ri]

        i = li if li != -1 else ri
        while stack:
            pi, is_right = stack.pop()
            children[is_right][pi] = i
            counts[pi] = counts[children[0][pi]] + counts[children[1][pi]] + 1
            i = pi

        return i

    def split(self, root, x):
        i = root
        children = self.children
        values = self.values
        counts = self.counts
        l_stack = []
        r_stack = []
        while i != -1:
            if x < values[i]:
                r_stack.append(i)
                i = children[0][i]
            else:
                l_stack.append(i)
                i = children[1][i]

        li, ri = -1, -1
        while l_stack:
            pi = l_stack.pop()
            children[1][pi] = li
            counts[pi] = counts[children[0][pi]] + counts[li] + 1
            li = pi
        while r_stack:
            pi = r_stack.pop()
            children[0][pi] = ri
            counts[pi] = counts[ri] + counts[children[1][pi]] + 1
            ri = pi

        return li, ri

    def insert(self, x):
        children = self.children
        values = self.values
        counts = self.counts

        ni = self.indices.pop()
        children[0][ni] = children[1][ni] = -1
        values[ni] = x
        counts[ni] = 1

        li, ri = self.split(self.root, x)
        self.root = self.merge(self.merge(li, ni), ri)

    def delete(self, x):
        children = self.children
        counts = self.counts
        li, mri = self.split(self.root, x - 1)
        mi, ri = self.split(mri, x)

        if mi == -1:
            self.root = self.merge(li, ri)
            return

        if counts[mi] == 1:
            self.indices.append(mi)
            self.root = self.merge(li, ri)
            return

        i = mi
        stack = []
        while i != -1:
            if children[0][i] != -1 and children[1][i] != -1:
                to_right = 1 if counts[children[0][i]] < counts[children[1][i]] else 0
                stack.append((i, to_right))
                i = children[to_right][i]
            else:
                if children[0][i] != -1:
                    if stack:
                        pi, is_right = stack[-1]
                        children[is_right][pi] = children[0][i]
                    else:
                        mi = children[0][i]
                elif children[1][i] != -1:
                    if stack:
                        pi, is_right = stack[-1]
                        children[is_right][pi] = children[1][i]
                    else:
                        mi = children[1][i]
                else:
                    pi, is_right = stack[-1]
                    children[is_right][pi] = -1
                break

        self.indices.append(i)
        while stack:
            pi, _ = stack.pop()
            counts[pi] -= 1

        self.root = self.merge(self.merge(li, mi), ri)

    def upper_bound(self, x, default=-1):
        i = self.root
        children = self.children
        values = self.values
        counts = self.counts
        y = default
        c = counts[i]
        j = 0
        while i != -1:
            if x < values[i]:
                y = values[i]
                c = j + counts[children[0][i]]
                i = children[0][i]
            else:
                j += counts[children[0][i]] + 1
                i = children[1][i]
        return y, c

    def lower_bound(self, x, default=-1):
        i = self.root
        children = self.children
        values = self.values
        counts = self.counts
        y = default
        c = counts[i]
        j = 0
        while i != -1:
            if x <= values[i]:
                y = values[i]
                c = j + counts[children[0][i]]
                i = children[0][i]
            else:
                j += counts[children[0][i]] + 1
                i = children[1][i]
        return y, c

    def get_k_th(self, k, default=-1):
        i = self.root
        children = self.children
        values = self.values
        counts = self.counts
        if counts[i] <= k:
            return default
        j = k
        while i != -1:
            left_count = counts[children[0][i]]
            if left_count == j:
                return values[i]
            elif left_count > j:
                i = children[0][i]
            else:
                j -= left_count + 1
                i = children[1][i]
        return default

    def debug_print(self):
        print('Lefts ', self.children[0])
        print('Rights', self.children[1])
        print('Values', self.values)
        print('Counts', self.counts)
        self._debug_print(self.root, 0)

    def _debug_print(self, i, depth):
        if i != -1:
            self._debug_print(self.children[0][i], depth + 1)
            print('      ' * depth, self.values[i], self.counts[i])
            self._debug_print(self.children[1][i], depth + 1)


h, w = map(int, sys.stdin.buffer.readline().split())
INF = 10 ** 18
rbst1 = RandomizedBinarySearchTree(w)
rbst2 = RandomizedBinarySearchTree(w)
rbst1.insert(INF)
rbst2.insert(INF)
for i in range(1, w + 1):
    rbst1.insert(i)
    rbst2.insert(0)
moves = [0] * (w + 1)
ans = [-1] * h

mp = map(int, sys.stdin.buffer.read().split())
for row, (a, b) in enumerate(zip(mp, mp)):
    c, _ = rbst1.lower_bound(a)
    stack = []
    while c <= b + 1:
        stack.append(c)
        c, _ = rbst1.lower_bound(c + 1)

    if len(stack) == 0:
        ans[row] = row + 1 + rbst2.get_k_th(0)
        continue

    found_nearest = b == w

    while stack:
        c = stack.pop()
        if found_nearest:
            rbst1.delete(c)
            rbst2.delete(moves[c])
        else:
            if c < b + 1:
                rbst1.delete(c)
                rbst1.insert(b + 1)
                rbst2.delete(moves[c])
                rbst2.insert(moves[c] + b + 1 - c)
                moves[b + 1] = moves[c] + b + 1 - c

            found_nearest = True

    move = rbst2.get_k_th(0, -1)
    if move == INF:
        break

    ans[row] = row + move + 1

print('\n'.join(map(str, ans)))


### FIXED CODE ###

import os
import sys

import numpy as np
from heapq import heappop, heappush, heapify


def solve(inp):
    def fenwick_add(arr, n, i, x):
        while i <= n:
            arr[i] += x
            i += i & -i

    def fenwick_sum(arr, i):
        result = 0
        while i > 0:
            result += arr[i]
            i ^= i & -i
        return result

    def fenwick_lower_bound(arr, n, log_n, x):
        sum_ = 0
        pos = 0
        for i in range(log_n, -1, -1):
            k = pos + (1 << i)
            if k < n and sum_ + arr[k] < x:
                sum_ += arr[k]
                pos += 1 << i
        return pos + 1

    def bit_length(x):
        res = 0
        while x:
            res += 1
            x >>= 1
        return res

    h = inp[0]
    w = inp[1]
    aaa = inp[2::2]
    bbb = inp[3::2]

    w1 = w + 1
    log_w = bit_length(w1)
    arr = np.zeros(w1 + 1, dtype=np.int64)
    for j in range(1, w1):
        arr[j] = j & -j
    fenwick_add(arr, w1, w1, 10 ** 18)
    horizontal = np.zeros(w + 1, dtype=np.int64)
    horizontal_rev = np.arange(w + 1, dtype=np.int64)
    q = [(0, j) for j in range(1, w + 1)]
    heapify(q)

    ans = np.full(h, -1, dtype=np.int64)

    for row in range(h):
        a = aaa[row]
        b = bbb[row]
        k = 1 if a == 1 else fenwick_sum(arr, a - 1) + 1
        c = fenwick_lower_bound(arr, w1, log_w, k)
        stack = []
        while c <= b + 1:
            stack.append(c)
            if c == w1:
                break
            k += 1
            c = fenwick_lower_bound(arr, w1, log_w, k)
        # print(a, b, k, c, horizontal, stack)

        if len(stack) == 0:
            ans[row] = row + q[0][0] + 1
            continue

        if stack[-1] == w1:
            found_nearest = True
            stack.pop()
        else:
            found_nearest = False
        stack.reverse()

        for c in stack:
            if found_nearest:
                fenwick_add(arr, w1, c, -1)
                horizontal[horizontal_rev[c]] = -1
            elif c == b + 1:
                found_nearest = True
            else:
                orig = horizontal_rev[c]
                horizontal[orig] = b + 1 - orig
                horizontal_rev[b + 1] = orig
                fenwick_add(arr, w1, c, -1)
                fenwick_add(arr, w1, b + 1, 1)
                heappush(q, (horizontal[orig], orig))
                found_nearest = True

        while q and q[0][0] != horizontal[q[0][1]]:
            heappop(q)

        if len(q) == 0:
            break

        ans[row] = row + q[0][0] + 1

    return ans


if sys.argv[-1] == 'ONLINE_JUDGE':
    from numba.pycc import CC

    cc = CC('my_module')
    cc.export('solve', '(i8[:],)')(solve)
    cc.compile()
    exit()

if os.name == 'posix':
    # noinspection PyUnresolvedReferences
    from my_module import solve
else:
    from numba import njit

    solve = njit('(i8[:],)', cache=True)(solve)
    print('compiled', file=sys.stderr)

inp = np.fromstring(sys.stdin.read(), dtype=np.int64, sep=' ')
ans = solve(inp)
print('\n'.join(map(str, ans)))