class UnionFind:
    def __init__(self,n):
        self.n = n
        self.parent_size = [-1]*n
 
    def leader(self,a):
        if self.parent_size[a] < 0:
            return a
        self.parent_size[a] = self.leader(self.parent_size[a])
        return self.parent_size[a]
 
    def merge(self,a,b):
        x, y = self.leader(a), self.leader(b)
        if x == y:
            return 
        if abs(self.parent_size[x]) < abs(self.parent_size[y]):
            x, y = y, x
        self.parent_size[x] += self.parent_size[y]
        self.parent_size[y] = x
        return 
 
    def same(self,a,b):
        return self.leader(a) == self.leader(b)
 
    def size(self,a):
        return abs(self.parent_size[self.leader(a)])
 
    def groups(self):
        result = [[] for _ in range(self.n)]
        for i in range(self.n):
            result[self.leader(i)].append(i)
        return [r for r in result if r != []]

N, Q = map(int, input().split())
AB = [list(map(int, input().split())) for _ in range(Q)]

L = []
for A, B in AB:
    L.append(A)
    L.append(B)
S = sorted(set(L))
idx = dict()
idxR = dict()
for i in range(len(S)):
    idx[S[i]] = i
    idxR[i] = S[i]

L = len(idx)
UF = UnionFind(L)
left = list(range(L))
right = list(range(L))
visited = [False]*L
ans = []
MAX = 1
for A, B in AB:
    l, r = idx[A], idx[B]
    visited[l] = True
    if 1 <= l and visited[l-1] and not UF.same(l-1, l) and idxR[l]-idxR[l-1] == 1:
        nl = left[UF.leader(l-1)]
        nr = right[UF.leader(l)]
        UF.merge(l-1, l)
        left[UF.leader(l)] = nl
        right[UF.leader(l)] = nr
        MAX = max(MAX, idxR[right[UF.leader(l)]]-idxR[left[UF.leader(l-1)]]+1)
    l = right[UF.leader(l)]
    while l < r:
        visited[l+1] = True
        nl = left[UF.leader(l)]
        nr = right[UF.leader(l+1)]
        UF.merge(l, l+1)
        left[UF.leader(l)] = nl
        right[UF.leader(l)] = nr
        l = nr
        MAX = max(MAX, idxR[right[UF.leader(l)]]-idxR[left[UF.leader(l)]]+1)
    if r < L-1 and visited[r+1] and not UF.same(r, r+1) and idxR[r+1]-idxR[r] == 1:
        nl = left[UF.leader(r)]
        nr = right[UF.leader(r+1)]
        UF.merge(r, r+1)
        left[UF.leader(r)] = nl
        right[UF.leader(r)] = nr
        MAX = max(MAX, idxR[right[UF.leader(r)]]-idxR[left[UF.leader(r)]]+1)
    ans.append(MAX)

print(*ans, sep="\n")