//c++ -std=gnu++14 a.cpp
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <iostream>
#include <istream>
#include <iterator>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>
#include <tuple>
#include <iomanip>
#include <climits>
#include <fstream>
#include <random>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
//typedef pair<ll, ll> P;
#define rep(i, n) for(int i = 0; i < (n); i++)
#define revrep(i, n) for(int i = (n)-1; i >= 0; i--)
#define pb push_back
#define f first
#define s second
#define chmin(x, y) x = min(x, y);
#define chmax(x, y) x = max(x, y);
#define len(x) ((int)(x).size())

//const ll INFL = LLONG_MAX;//10^18 = 2^60
const ll INFL = 1LL<<60;
//const int INF = INT_MAX;
const int INF = 1 << 30;//10^9
const ll MOD = 1000000007;
//const ll MOD = 998244353;
double EPS = 1e-10;

vector<ll> dy = {0, 1, 0, -1, 1, 1, -1, -1, 0};
vector<ll> dx = {1, 0, -1, 0, 1, -1, 1, -1, 0};

void pres(double A){printf("%.9lf\n", A);}
void BinarySay(ll x, ll y = 60){rep(i, y) cout << (x>>(y-1-i) & 1); cout << endl;}
ll cnt_bit(ll x){return __builtin_popcountll(x);}

ll pow_long(ll x, ll k){
  ll res = 1;
  while(k > 0){
    if(k % 2) res *= x;
    x *= x; k /= 2;
  }
  return res;
}

ll pow_mod(ll x, ll k){
  ll res = 1;
  while(k > 0){
    if(k % 2){
      res *= x; res %= MOD;
    }
    x *= x; x %= MOD;
    k /= 2;
  }
  return res;
}

ll inverse(ll x){return pow_mod(x, MOD - 2);};

ll gcd(ll a, ll b){
    if(b == 0) return a;
    return gcd(b, a % b);
}

ll lcm(ll x, ll y){
  ll res = x / gcd(x, y);
  res *= y;
  return res;
};


//コンビネーション
const int MAXcomb = 2000010;
ll fac[MAXcomb], finv[MAXcomb], inv[MAXcomb];
//facはn!,finvは1/n!
//invは逆元
void COMinit(){
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for(int i = 2; i < MAXcomb; i++){
        fac[i] = fac[i-1] * i % MOD;
        inv[i] = MOD - inv[MOD%i] * (MOD/i) % MOD;
        finv[i] = finv[i-1] * inv[i] % MOD;
    }
}
ll comb(int n, int k){
    if(n < k) return 0;
    if(n < 0 || k < 0) return 0;
    return fac[n] * finv[k] % MOD * finv[n-k] % MOD;
}


ll disit(ll s, ll base = 10){
  ll res = 0;
  while(s){
    res++;
    s /= base;
  }
  return res;
}

//区間変更、区間最大
const int N_ = 1<<18;
int seg[2 * N_ - 1], lazy[2 * N_ - 1];

void eval(int k, int l, int r){
  if(lazy[k] == 0) return;
  seg[k] = lazy[k];
  if(r - l > 1){
    lazy[2 * k + 1] = lazy[k];
    lazy[2 * k + 2] = lazy[k];
  }
  lazy[k] = 0;
}

void update(int a, int b, int x, int k = 0, int l = 0, int r = N_){
  eval(k, l, r);
  if(r <= a || b <= l) return;
  if(a <= l && r <= b){
    lazy[k] = x;
    eval(k, l, r);
    return;
  }
  update(a, b, x, 2 * k + 1, l, (l + r) / 2);
  update(a, b, x, 2 * k + 2, (l + r) / 2, r);
  seg[k] = max(seg[2 * k + 1], seg[2 * k + 2]);
  return;
}

int getmaximum(int a, int b, int k = 0, int l = 0, int r = N_){
  if(r <= a || b <= l) return -1;
  eval(k, l, r);
  if(a <= l && r <= b) return seg[k];
  int res1 = getmaximum(a, b, 2 * k + 1, l, (l + r) / 2);
  int res2 = getmaximum(a, b, 2 * k + 2, (l + r) / 2, r);
  return max(res1, res2);
}



int seg2[2 * N_ - 1], lazy2[2 * N_ - 1];
void eval2(int k, int l, int r){
  if(lazy2[k] == 0) return;
  seg2[k] = lazy2[k];
  if(r - l > 1){
    lazy2[2 * k + 1] = lazy2[k];
    lazy2[2 * k + 2] = lazy2[k];
  }
  lazy2[k] = 0;
}

void update2(int a, int b, int x, int k = 0, int l = 0, int r = N_){
  eval2(k, l, r);
  if(r <= a || b <= l) return;
  if(a <= l && r <= b){
    lazy2[k] = x;
    eval2(k, l, r);
    return;
  }
  update2(a, b, x, 2 * k + 1, l, (l + r) / 2);
  update2(a, b, x, 2 * k + 2, (l + r) / 2, r);
  seg2[k] = min(seg2[2 * k + 1], seg2[2 * k + 2]);
  return;
}

int getminimum2(int a, int b, int k = 0, int l = 0, int r = N_){
  if(r <= a || b <= l) return INF;
  eval2(k, l, r);
  if(a <= l && r <= b) return seg2[k];
  int res = INF;
  res = min(res, getminimum2(a, b, 2 * k + 1, l, (l + r) / 2));
  res = min(res, getminimum2(a, b, 2 * k + 2, (l + r) / 2, r));
  return res;
}


int H, W;
int A[200010], B[200010];
void solve(){
  cin >> H >> W;
  rep(i, H){
    cin >> A[i] >> B[i];
  }
  rep(i, W+1){
    update(i, i+1, i+10);
  }
  update2(1, W+1, 10);
  rep(i, H){
    int x = getmaximum(A[i]-1, A[i]) - 10;
    int y = getmaximum(A[i], A[i]+1) - 10;
    int z = getmaximum(B[i], B[i]+1) - 10;
    int w = getmaximum(B[i]+1, B[i]+2) - 10;
    update(A[i], B[i] + 1, x + 10);
    if(x != y){
      update2(y, y+1, INF);
    }
    update2(y+1, z+1, INF);
    if(w != 0 && x != w){
      update2(w, w+1, B[i]+1-w+10);
    }
    int ans = getminimum2(1, W+1)-10;
    if(ans > W){
      cout << -1 << endl;
    }else{
      cout << ans + i+1 << endl;
    }
  }
}

int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  solve();
}


Measured memory_bytes: 11544