#include <bits/stdc++.h>
using namespace std;

typedef long long   signed int LL;
typedef long long unsigned int LU;

#define incID(i, l, r) for(int i = (l)    ; i <  (r); i++)
#define incII(i, l, r) for(int i = (l)    ; i <= (r); i++)
#define decID(i, l, r) for(int i = (r) - 1; i >= (l); i--)
#define decII(i, l, r) for(int i = (r)    ; i >= (l); i--)
#define  inc(i, n) incID(i, 0, n)
#define inc1(i, n) incII(i, 1, n)
#define  dec(i, n) decID(i, 0, n)
#define dec1(i, n) decII(i, 1, n)

#define inII(v, l, r) ((l) <= (v) && (v) <= (r))
#define inID(v, l, r) ((l) <= (v) && (v) <  (r))

#define PB push_back
#define EB emplace_back
#define MP make_pair
#define FI first
#define SE second
#define PQ priority_queue

#define  ALL(v)  v.begin(),  v.end()
#define RALL(v) v.rbegin(), v.rend()
#define  FOR(it, v) for(auto it =  v.begin(); it !=  v.end(); ++it)
#define RFOR(it, v) for(auto it = v.rbegin(); it != v.rend(); ++it)

template<typename T> bool   setmin(T & a, T b) { if(b <  a) { a = b; return true; } else { return false; } }
template<typename T> bool   setmax(T & a, T b) { if(b >  a) { a = b; return true; } else { return false; } }
template<typename T> bool setmineq(T & a, T b) { if(b <= a) { a = b; return true; } else { return false; } }
template<typename T> bool setmaxeq(T & a, T b) { if(b >= a) { a = b; return true; } else { return false; } }
template<typename T> T gcd(T a, T b) { return (b == 0 ? a : gcd(b, a % b)); }
template<typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }

// ---- ----

LL d, q, ma;
map<LL, LL> mp;

bool contact(LL a, LL b, LL c, LL d) {
	return ! (b < c || d < a);
}

void f() {
	FOR(it, mp) { cout << it->FI << "_" << it->SE - 1 << "  "; } cout << endl;
}

int main() {
	cin >> d >> q;
	mp[-2] = -1;
	mp[d + 1] = d + 2;
	// f();
	inc(qq, q) {
		LL a, b;
		cin >> a >> b;
		b++;
		
		auto l = mp.lower_bound(a); l--;
		auto r = mp.upper_bound(b); r--;
		if(! contact(a, b, l -> FI, l -> SE)) { l++; }
		
		LL x = min(a, l -> FI);
		LL y = max(b, r -> SE);
		mp.erase(l, ++r);
		mp[x] = y;
		setmax(ma, y - x);
		
		cout << ma << "\n";
		
		// f();
	}
	
	return 0;
}