#include"bits/stdc++.h"
using namespace std;using ll=long long;using vi=vector<int>;using vvi=vector<vi>;using vl=vector<ll>;using vvl=vector<vl>;using P=pair<int,int>;using PL=pair<ll,ll>;using vp=vector<P>;using vpl=vector<PL>;
#define pqueue priority_queue
template<typename T>constexpr auto inf=numeric_limits<T>::max()/2;constexpr int INF=inf<int>,MOD=1000000007;constexpr ll LINF=inf<ll>;
#define _ol3(_1,_2,_3,name,...)name
#define _rep(i,n)_repi(i,0,n)
#define _repi(i,a,b)for(int i=a,i##_l=(b);i<i##_l;++i)
#define REP(...)_ol3(__VA_ARGS__,_repi,_rep,)(__VA_ARGS__)
#define REPR(i,n)for(int i=n-1;i>=0;--i)
#define REPA(i,v)REP(i,(v).size())
#define all(v)(v).begin(),(v).end()
#define rall(v)(v).rbegin(),(v).rend()
#define bit(n)(1ll<<(n))
#define F first
#define S second
#define endl '\n'
void _print(ostream&){}template<class T,class...U>void _print(ostream&s,const T&t,const U&...u){s<<t<<(sizeof...(u)?' ':'\n');_print(s,u...);}
template<class...T>void print(const T&...t){_print(cout,t...);}template<class...T>void dprint(const T&...t){_print(cerr,t...);}
#ifndef LOCAL
struct osd{template<class T>osd&operator<<(const T&t){return*this;}};osd cer_;
#define dprint(...)
#define cerr cer_
#endif
#define dbg(x) dprint("@l",__LINE__,':',#x,'=',x)
#define cho(n,a,b)print((n)?a:b)
void YES(int n){cho(n,"YES","NO");}void Yes(int n){cho(n,"Yes","No");}void Poss(int n){cho(n,"Possible","Impossible");}
template<class T, class U>bool chmax(T&a,const U&b){bool x=a<b;x?a=b:b;return x;}template<class T, class U>bool chmin(T&a,const U&b){bool x=a>b;x?a=b:b;return x;}
template<class T, class U>auto max(const T&a,const U&b){return a<b?b:a;}template<class T, class U>auto min(const T&a,const U&b){return a<b?a:b;}
template<class T,class U>ostream&operator<<(ostream&o,const pair<T,U>&p){return o<<p.F<<' '<<p.S;}template<class T,class U>istream&operator>>(istream&i,pair<T,U>&p){return i>>p.F>>p.S;}
template<class T>class iterable{static false_type c(string v);template<class U>static auto c(U v)->decltype(all(v),true_type());static false_type c(...);public:const static bool value=decltype(c(declval<T>()))::value;};
template<class T,enable_if_t<iterable<T>::value,int> =0>ostream&operator<<(ostream&o,const T&v){for(auto&&i:v)o<<i<<' ';return o;}
template<class T>istream&operator>>(istream&i,vector<T>&v){for(T&j:v)i>>j;return i;}template<class T>vector<T>&operator<<(vector<T>&v,const T&t){v.push_back(t);return v;}
template<class T,class U>queue<T,U>&operator<<(queue<T,U>&v, const T&t){v.push(t);return v;}template<class T,class U>queue<T,U>&operator>>(queue<T,U>&v, T&t){t=v.front();v.pop();return v;}
template<class T,class U,class V>pqueue<T,U,V>&operator<<(pqueue<T,U,V>&v, const T&t){v.push(t);return v;}template<class T,class U,class V>pqueue<T,U,V>&operator>>(pqueue<T,U,V>&v, T&t){t=v.front();v.pop();return v;}
template<class T,class U>stack<T,U>&operator<<(stack<T,U>&v, const T&t){v.push(t);return v;}template<class T,class U>stack<T,U>&operator>>(stack<T,U>&v, T&t){t=v.front();v.pop();return v;}
template<class T,class U,class V>set<T,U,V>&operator<<(set<T,U,V>&v,const T&t){v.insert(t);return v;}template<class T,class U,class V>multiset<T,U,V>&operator<<(multiset<T,U,V>&v,const T&t){v.insert(t);return v;}
template<class T,enable_if_t<is_integral<T>::value,int> =0>T mod(T a, T b){if(a>0)return a%b;return b-(-a%b);}template<class T,enable_if_t<is_floating_point<T>::value,int> =0>T mod(T a, T b){if(a>0)return fmod(a,b);return b-fmod(-a,b);}
template<class T,class U>pair<T,U>&operator+=(pair<T,U>&a, const pair<T,U>&b){a.F+=b.F;a.S+=b.S;return a;}template<class T,class U>pair<T,U> operator+(const pair<T,U>&a, const pair<T,U>&b){auto r=a;return r+=b;}
template<class T,class U>pair<T,U>&operator-=(pair<T,U>&a, const pair<T,U>&b){a.F-=b.F;a.S-=b.S;return a;}template<class T,class U>pair<T,U> operator-(const pair<T,U>&a, const pair<T,U>&b){auto r=a;return r-=b;}
template<class T,class U>pair<T,U> operator-(const pair<T,U>&a){return {-a.F, -a.S};}
template<class T,class U>double norm(const pair<T,U>&p){return norm(p.F)+norm(p.S);}template<class T,class U>double abs(const pair<T,U>&p){return sqrt(norm(p));}

int main(){
    cin.tie(0);ios::sync_with_stdio(0);
    cout<<fixed<<setprecision(10);
    int h,w;
    cin>>h>>w;
    vp a(h);
    cin>>a;
    REP(i,h){
        a[i].F--;
        a[i].S--;
    }

    multiset<int> m;
    map<int, int> s;
    REP(i,w) {
        m << 0;
        s[i] = i;
    }
    dbg(m);
    dbg(s);
    REP(i, h) {
        auto iter = s.lower_bound(a[i].F);
        auto jter = s.lower_bound(a[i].S+1);
        if (iter != jter) {
            P ma = *prev(jter);
            for(auto j = iter; j != jter; ++j) {
                dbg(*j);
                m.erase(m.find(j->F - j->S));
            }
            s.erase(iter, jter);
            if (a[i].S + 1 < w) {
                auto kter = s.find(a[i].S+1);
                if (kter != s.end()) {
                    dbg(*kter);
                    if (chmax(kter->S, ma.S)) {
                        m.erase(m.find(kter->S - kter->F));
                        m << a[i].S+1 - ma.S;
                    }
                } else {
                    s[a[i].S+1] = ma.S;
                    m << a[i].S+1 - ma.S;
                }
            }
        }
        dbg(m);
        dbg(s);
        if (m.size())
            cout << *m.begin() + i + 1 << endl;
        else
            cout << -1 << endl;

    }



}


Measured memory_bytes: 23520