class SegmentTreeDual():
    def __init__(self, init, unitX, unitA, g, h):
        self.g = g # (X, A, size) -> X
        self.h = h # (A, A) -> A
        self.unitA = unitA
        if type(init) == int:
            self.n = init
            self.n = 1 << (self.n - 1).bit_length()
            self.X = [unitX] * (self.n * 2)
            self.size = [1] * (self.n * 2)
        else:
            self.n = len(init)
            self.n = 1 << (self.n - 1).bit_length()
            self.X = [unitX] * self.n + init + [unitX] * (self.n - len(init))
            self.size = [0] * self.n + [1] * len(init) + [0] * (self.n - len(init))
    
        for i in range(self.n - 1, 0, -1):
            self.size[i] = self.size[i*2] + self.size[i*2|1]
        
        self.A = [unitA] * (self.n * 2)
        
    def calc(self, i):
        return self.g(self.X[i], self.A[i], self.size[i])
    
    def propagate(self, i):
        self.X[i] = self.g(self.X[i], self.A[i], self.size[i])
        self.A[i*2] = self.h(self.A[i*2], self.A[i])
        self.A[i*2|1] = self.h(self.A[i*2|1], self.A[i])
        self.A[i] = self.unitA
        
    def propagate_above(self, i):
        H = i.bit_length()
        for h in range(H, 0, -1):
            self.propagate(i >> h)
    
    def propagate_all(self):
        for i in range(1, self.n):
            self.propagate(i)
    
    def getvalue(self, i):
        i += self.n
        self.propagate_above(i)
        return self.calc(i)
    
    def operate_range(self, l, r, a):
        l += self.n
        r += self.n
        l0, r0 = l // (l & -l), r // (r & -r) - 1
        self.propagate_above(l0)
        self.propagate_above(r0)
        while l < r:
            if l & 1:
                self.A[l] = self.h(self.A[l], a)
                l += 1
            if r & 1:
                r -= 1
                self.A[r] = self.h(self.A[r], a)
            l >>= 1
            r >>= 1
    
    def debug(self):
        print("self.n =", self.n)
        deX = []
        deA = []
        deS = []
        a, b = self.n, self.n * 2
        while b:
            deX.append(self.X[a:b])
            deA.append(self.A[a:b])
            deS.append(self.size[a:b])
            a, b = a//2, a
        print("--- debug ---")
        for d in deX[::-1]:
            print(d)
        print("--- ---")
        for d in deA[::-1]:
            print(d)
        print("--- ---")
        for d in deS[::-1]:
            print(d)
        print("--- ---")

d, Q = map(int, input().split())
S = set()
X = []
for _ in range(Q):
    a, b = map(int, input().split())
    S.add(a)
    S.add(b + 1)
    S.add(a-1)
    S.add(b + 2)
    X.append((a, b+1))

I = sorted(list(S))
D = {a: i for i, a in enumerate(I)}
Y = []
for a, b in X:
    Y.append((D[a], D[b]))

N = len(I)

inf = 1 << 18 + 1
g = lambda x, a, s: min(x, a)
h = lambda a, b: min(a, b)
unitA = inf
unitX = inf
st_min = SegmentTreeDual(N, unitX, unitA, g, h)

g = lambda x, a, s: max(x, a)
h = lambda a, b: max(a, b)
unitA = -1
unitX = -1
st_max = SegmentTreeDual(N, unitX, unitA, g, h)

ans = 0
for l, r in Y:
    mi = min(st_min.getvalue(l-1), l)
    ma = max(st_max.getvalue(r), r)
    ans = max(ans, I[ma] - I[mi])
    st_min.operate_range(mi, ma, mi)
    st_max.operate_range(mi, ma, ma)
    print(ans)