#pragma region kyopro_template
#define Nyaan_template
#include <immintrin.h>
#include <bits/stdc++.h>
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define each(x, v) for (auto &x : v)
#define all(v) (v).begin(), (v).end()
#define sz(v) ((int)(v).size())
#define mem(a, val) memset(a, val, sizeof(a))
#define ini(...)   \
  int __VA_ARGS__; \
  in(__VA_ARGS__)
#define inl(...)         \
  long long __VA_ARGS__; \
  in(__VA_ARGS__)
#define ins(...)      \
  string __VA_ARGS__; \
  in(__VA_ARGS__)
#define inc(...)    \
  char __VA_ARGS__; \
  in(__VA_ARGS__)
#define in2(s, t)                           \
  for (int i = 0; i < (int)s.size(); i++) { \
    in(s[i], t[i]);                         \
  }
#define in3(s, t, u)                        \
  for (int i = 0; i < (int)s.size(); i++) { \
    in(s[i], t[i], u[i]);                   \
  }
#define in4(s, t, u, v)                     \
  for (int i = 0; i < (int)s.size(); i++) { \
    in(s[i], t[i], u[i], v[i]);             \
  }
#define rep(i, N) for (long long i = 0; i < (long long)(N); i++)
#define repr(i, N) for (long long i = (long long)(N)-1; i >= 0; i--)
#define rep1(i, N) for (long long i = 1; i <= (long long)(N); i++)
#define repr1(i, N) for (long long i = (N); (long long)(i) > 0; i--)
#define reg(i, a, b) for (long long i = (a); i < (b); i++)
#define die(...)      \
  do {                \
    out(__VA_ARGS__); \
    return;           \
  } while (0)
using namespace std;
using ll = long long;
template <class T>
using V = vector<T>;
using vi = vector<int>;
using vl = vector<long long>;
using vvi = vector<vector<int>>;
using vd = V<double>;
using vs = V<string>;
using vvl = vector<vector<long long>>;
using P = pair<long long, long long>;
using vp = vector<P>;
using pii = pair<int, int>;
using vpi = vector<pair<int, int>>;
constexpr int inf = 1001001001;
constexpr long long infLL = (1LL << 61) - 1;
template <typename T, typename U>
inline bool amin(T &x, U y) {
  return (y < x) ? (x = y, true) : false;
}
template <typename T, typename U>
inline bool amax(T &x, U y) {
  return (x < y) ? (x = y, true) : false;
}
template <typename T, typename U>
ostream &operator<<(ostream &os, const pair<T, U> &p) {
  os << p.first << " " << p.second;
  return os;
}
template <typename T, typename U>
istream &operator>>(istream &is, pair<T, U> &p) {
  is >> p.first >> p.second;
  return is;
}
template <typename T>
ostream &operator<<(ostream &os, const vector<T> &v) {
  int s = (int)v.size();
  for (int i = 0; i < s; i++) os << (i ? " " : "") << v[i];
  return os;
}
template <typename T>
istream &operator>>(istream &is, vector<T> &v) {
  for (auto &x : v) is >> x;
  return is;
}
void in() {}
template <typename T, class... U>
void in(T &t, U &... u) {
  cin >> t;
  in(u...);
}
void out() { cout << "\n"; }
template <typename T, class... U>
void out(const T &t, const U &... u) {
  cout << t;
  if (sizeof...(u)) cout << " ";
  out(u...);
}

#ifdef NyaanDebug
#define trc(...)                   \
  do {                             \
    cerr << #__VA_ARGS__ << " = "; \
    dbg_out(__VA_ARGS__);          \
  } while (0)
#define trca(v, N)       \
  do {                   \
    cerr << #v << " = "; \
    array_out(v, N);     \
  } while (0)
#define trcc(v)                             \
  do {                                      \
    cerr << #v << " = {";                   \
    each(x, v) { cerr << " " << x << ","; } \
    cerr << "}" << endl;                    \
  } while (0)
template <typename T>
void _cout(const T &c) {
  cerr << c;
}
void _cout(const int &c) {
  if (c == 1001001001)
    cerr << "inf";
  else if (c == -1001001001)
    cerr << "-inf";
  else
    cerr << c;
}
void _cout(const unsigned int &c) {
  if (c == 1001001001)
    cerr << "inf";
  else
    cerr << c;
}
void _cout(const long long &c) {
  if (c == 1001001001 || c == (1LL << 61) - 1)
    cerr << "inf";
  else if (c == -1001001001 || c == -((1LL << 61) - 1))
    cerr << "-inf";
  else
    cerr << c;
}
void _cout(const unsigned long long &c) {
  if (c == 1001001001 || c == (1LL << 61) - 1)
    cerr << "inf";
  else
    cerr << c;
}
template <typename T, typename U>
void _cout(const pair<T, U> &p) {
  cerr << "{ ";
  _cout(p.fi);
  cerr << ", ";
  _cout(p.se);
  cerr << " } ";
}
template <typename T>
void _cout(const vector<T> &v) {
  int s = v.size();
  cerr << "{ ";
  for (int i = 0; i < s; i++) {
    cerr << (i ? ", " : "");
    _cout(v[i]);
  }
  cerr << " } ";
}
template <typename T>
void _cout(const vector<vector<T>> &v) {
  cerr << "[ ";
  for (const auto &x : v) {
    cerr << endl;
    _cout(x);
    cerr << ", ";
  }
  cerr << endl << " ] ";
}
void dbg_out() { cerr << endl; }
template <typename T, class... U>
void dbg_out(const T &t, const U &... u) {
  _cout(t);
  if (sizeof...(u)) cerr << ", ";
  dbg_out(u...);
}
template <typename T>
void array_out(const T &v, int s) {
  cerr << "{ ";
  for (int i = 0; i < s; i++) {
    cerr << (i ? ", " : "");
    _cout(v[i]);
  }
  cerr << " } " << endl;
}
template <typename T>
void array_out(const T &v, int H, int W) {
  cerr << "[ ";
  for (int i = 0; i < H; i++) {
    cerr << (i ? ", " : "");
    array_out(v[i], W);
  }
  cerr << " ] " << endl;
}
#else
#define trc(...)
#define trca(...)
#define trcc(...)
#endif

inline int popcnt(unsigned long long a) { return __builtin_popcountll(a); }
inline int lsb(unsigned long long a) { return __builtin_ctzll(a); }
inline int msb(unsigned long long a) { return 63 - __builtin_clzll(a); }
template <typename T>
inline int getbit(T a, int i) {
  return (a >> i) & 1;
}
template <typename T>
inline void setbit(T &a, int i) {
  a |= (1LL << i);
}
template <typename T>
inline void delbit(T &a, int i) {
  a &= ~(1LL << i);
}
template <typename T>
int lb(const vector<T> &v, const T &a) {
  return lower_bound(begin(v), end(v), a) - begin(v);
}
template <typename T>
int ub(const vector<T> &v, const T &a) {
  return upper_bound(begin(v), end(v), a) - begin(v);
}
template <typename T>
int btw(T a, T x, T b) {
  return a <= x && x < b;
}
template <typename T, typename U>
T ceil(T a, U b) {
  return (a + b - 1) / b;
}
constexpr long long TEN(int n) {
  long long ret = 1, x = 10;
  while (n) {
    if (n & 1) ret *= x;
    x *= x;
    n >>= 1;
  }
  return ret;
}
template <typename T>
vector<T> mkrui(const vector<T> &v) {
  vector<T> ret(v.size() + 1);
  for (int i = 0; i < int(v.size()); i++) ret[i + 1] = ret[i] + v[i];
  return ret;
};
template <typename T>
vector<T> mkuni(const vector<T> &v) {
  vector<T> ret(v);
  sort(ret.begin(), ret.end());
  ret.erase(unique(ret.begin(), ret.end()), ret.end());
  return ret;
}
template <typename F>
vector<int> mkord(int N, F f) {
  vector<int> ord(N);
  iota(begin(ord), end(ord), 0);
  sort(begin(ord), end(ord), f);
  return ord;
}
template <typename T = int>
vector<T> mkiota(int N) {
  vector<T> ret(N);
  iota(begin(ret), end(ret), 0);
  return ret;
}
template <typename T>
vector<int> mkinv(vector<T> &v) {
  vector<int> inv(v.size());
  for (int i = 0; i < (int)v.size(); i++) inv[v[i]] = i;
  return inv;
}

struct IoSetupNya {
  IoSetupNya() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(15);
    cerr << fixed << setprecision(7);
  }
} iosetupnya;

void solve();
int main() { solve(); }

#pragma endregion
using namespace std;

template <typename E, E INF>
struct UpdateMin_LazySegmentTree {
  int n, height;
  using T = E;
  T f(T a, T b) { return min(a, b); };
  T g(T, E b) { return b; };
  E h(E, E b) { return b; };
  T ti = INF;
  E ei = INF;
  vector<T> dat;
  vector<E> laz;

  UpdateMin_LazySegmentTree(const vector<E> &v) { build(v); }

  void init(int n_) {
    n = 1;
    height = 0;
    while (n < n_) n <<= 1, height++;
    dat.assign(2 * n, ti);
    laz.assign(2 * n, ei);
  }

  void build(const vector<E> &v) {
    int n_ = v.size();
    init(n_);
    for (int i = 0; i < n_; i++) dat[n + i] = v[i];
    for (int i = n - 1; i; i--)
      dat[i] = f(dat[(i << 1) | 0], dat[(i << 1) | 1]);
  }

  inline T reflect(int k) { return laz[k] == ei ? dat[k] : g(dat[k], laz[k]); }

  inline void propagate(int k) {
    if (laz[k] == ei) return;
    laz[(k << 1) | 0] = h(laz[(k << 1) | 0], laz[k]);
    laz[(k << 1) | 1] = h(laz[(k << 1) | 1], laz[k]);
    dat[k] = reflect(k);
    laz[k] = ei;
  }

  inline void thrust(int k) {
    for (int i = height; i; i--) propagate(k >> i);
  }

  inline void recalc(int k) {
    while (k >>= 1) dat[k] = f(reflect((k << 1) | 0), reflect((k << 1) | 1));
  }

  void update(int a, int b, E x) {
    if (a >= b) return;
    thrust(a += n);
    thrust(b += n - 1);
    for (int l = a, r = b + 1; l < r; l >>= 1, r >>= 1) {
      if (l & 1) laz[l] = h(laz[l], x), l++;
      if (r & 1) --r, laz[r] = h(laz[r], x);
    }
    recalc(a);
    recalc(b);
  }

  void set_val(int a, T x) {
    thrust(a += n);
    dat[a] = x;
    laz[a] = ei;
    recalc(a);
  }

  T query(int a, int b) {
    if (a >= b) return ti;
    thrust(a += n);
    thrust(b += n - 1);
    T vl = ti, vr = ti;
    for (int l = a, r = b + 1; l < r; l >>= 1, r >>= 1) {
      if (l & 1) vl = f(vl, reflect(l++));
      if (r & 1) vr = f(reflect(--r), vr);
    }
    return f(vl, vr);
  }
};

void solve() {
  ini(H, W);
  vl a(H), b(H);
  in2(a, b);
  each(x, a) x--;

  UpdateMin_LazySegmentTree<ll, infLL> seg(vl(W, 0));

  vl seg2ini(W);
  rep(i, W) seg2ini[i] = 0 - i;
  UpdateMin_LazySegmentTree<ll, infLL> seg2(seg2ini);

  vl ans(H, -1);
  rep(i, H) {
    ll nx = inf;
    if (b[i] != W) {
      ll mi = seg2.query(a[i], b[i]);
      if (mi < inf) nx = mi + b[i];
    }
    trc(i, a[i], b[i]);
    rep(i, W) trc(seg.query(i, i + 1), seg2.query(i, i + 1));
    seg.update(a[i], b[i], inf);
    seg2.update(a[i], b[i], inf);
    rep(i, W) trc(seg.query(i, i + 1), seg2.query(i, i + 1));
    if (nx < inf) {
      if (seg.query(b[i], b[i] + 1) > nx) {
        seg.update(b[i], b[i] + 1, nx);
        seg2.update(b[i], b[i] + 1, nx - b[i]);
      }
    }
    trc(i, a[i], b[i]);
    rep(i, W) trc(seg.query(i, i + 1), seg2.query(i, i + 1));
    ans[i] = i + 1 + seg.query(0, W);
    if (ans[i] >= TEN(6)) {
      ans[i] = -1;
      break;
    }
  }
  each(x, ans) out(x);

  /*
  vi cnt(W + 1, 0);
  int mi = 0;
  cnt[0] = W;
  cnt[W] = inf;
  set<pair<int,int>> s;
  rep(i,W) s.insert(pair<int,int>{i, 0});

  auto ers = [&](pii p){
    cnt[p.second]--;
    if(mi == p.second && cnt[p.second] == 0){
      while(cnt[mi] == 0) mi++;
    }
  };
  auto add = [&](pii p){

  };


  vi ans(H, -1);
  vpi st;
  rep(i, H) {
    st.clear();
    auto it = s.lower_bound({a[i], -inf});
    pii nx;
    if(it->first != a[i]){
      if(it != s.begin()) {
        --it;
        ers(*it);
        nx = {i, it->second + a[i] - it->first};
        ++it;
      } else {
        if(it->first <= b[i]){

        }
      }
    }else {

    }

  }
  */
}

Measured memory_bytes: 25788