#include <bits/stdc++.h>

namespace atcoder {

namespace internal {

// @param n `0 <= n`
// @return minimum non-negative `x` s.t. `n <= 2**x`
int ceil_pow2(int n) {
    int x = 0;
    while ((1U << x) < (unsigned int)(n)) x++;
    return x;
}

// @param n `1 <= n`
// @return minimum non-negative `x` s.t. `(n & (1 << x)) != 0`
int bsf(unsigned int n) {
#ifdef _MSC_VER
    unsigned long index;
    _BitScanForward(&index, n);
    return index;
#else
    return __builtin_ctz(n);
#endif
}

}  // namespace internal

}  // namespace atcoder

namespace atcoder {

template <class S,
          S (*op)(S, S),
          S (*e)(),
          class F,
          S (*mapping)(F, S),
          F (*composition)(F, F),
          F (*id)()>
struct lazy_segtree {
  public:
    lazy_segtree() : lazy_segtree(0) {}
    lazy_segtree(int n) : lazy_segtree(std::vector<S>(n, e())) {}
    lazy_segtree(const std::vector<S>& v) : _n(int(v.size())) {
        log = internal::ceil_pow2(_n);
        size = 1 << log;
        d = std::vector<S>(2 * size, e());
        lz = std::vector<F>(size, id());
        for (int i = 0; i < _n; i++) d[size + i] = v[i];
        for (int i = size - 1; i >= 1; i--) {
            update(i);
        }
    }

    void set(int p, S x) {
        assert(0 <= p && p < _n);
        p += size;
        for (int i = log; i >= 1; i--) push(p >> i);
        d[p] = x;
        for (int i = 1; i <= log; i++) update(p >> i);
    }

    S get(int p) {
        assert(0 <= p && p < _n);
        p += size;
        for (int i = log; i >= 1; i--) push(p >> i);
        return d[p];
    }

    S prod(int l, int r) {
        assert(0 <= l && l <= r && r <= _n);
        if (l == r) return e();

        l += size;
        r += size;

        for (int i = log; i >= 1; i--) {
            if (((l >> i) << i) != l) push(l >> i);
            if (((r >> i) << i) != r) push(r >> i);
        }

        S sml = e(), smr = e();
        while (l < r) {
            if (l & 1) sml = op(sml, d[l++]);
            if (r & 1) smr = op(d[--r], smr);
            l >>= 1;
            r >>= 1;
        }

        return op(sml, smr);
    }

    S all_prod() { return d[1]; }

    void apply(int p, F f) {
        assert(0 <= p && p < _n);
        p += size;
        for (int i = log; i >= 1; i--) push(p >> i);
        d[p] = mapping(f, d[p]);
        for (int i = 1; i <= log; i++) update(p >> i);
    }
    void apply(int l, int r, F f) {
        assert(0 <= l && l <= r && r <= _n);
        if (l == r) return;

        l += size;
        r += size;

        for (int i = log; i >= 1; i--) {
            if (((l >> i) << i) != l) push(l >> i);
            if (((r >> i) << i) != r) push((r - 1) >> i);
        }

        {
            int l2 = l, r2 = r;
            while (l < r) {
                if (l & 1) all_apply(l++, f);
                if (r & 1) all_apply(--r, f);
                l >>= 1;
                r >>= 1;
            }
            l = l2;
            r = r2;
        }

        for (int i = 1; i <= log; i++) {
            if (((l >> i) << i) != l) update(l >> i);
            if (((r >> i) << i) != r) update((r - 1) >> i);
        }
    }

    template <bool (*g)(S)> int max_right(int l) {
        return max_right(l, [](S x) { return g(x); });
    }
    template <class G> int max_right(int l, G g) {
        assert(0 <= l && l <= _n);
        assert(g(e()));
        if (l == _n) return _n;
        l += size;
        for (int i = log; i >= 1; i--) push(l >> i);
        S sm = e();
        do {
            while (l % 2 == 0) l >>= 1;
            if (!g(op(sm, d[l]))) {
                while (l < size) {
                    push(l);
                    l = (2 * l);
                    if (g(op(sm, d[l]))) {
                        sm = op(sm, d[l]);
                        l++;
                    }
                }
                return l - size;
            }
            sm = op(sm, d[l]);
            l++;
        } while ((l & -l) != l);
        return _n;
    }

    template <bool (*g)(S)> int min_left(int r) {
        return min_left(r, [](S x) { return g(x); });
    }
    template <class G> int min_left(int r, G g) {
        assert(0 <= r && r <= _n);
        assert(g(e()));
        if (r == 0) return 0;
        r += size;
        for (int i = log; i >= 1; i--) push((r - 1) >> i);
        S sm = e();
        do {
            r--;
            while (r > 1 && (r % 2)) r >>= 1;
            if (!g(op(d[r], sm))) {
                while (r < size) {
                    push(r);
                    r = (2 * r + 1);
                    if (g(op(d[r], sm))) {
                        sm = op(d[r], sm);
                        r--;
                    }
                }
                return r + 1 - size;
            }
            sm = op(d[r], sm);
        } while ((r & -r) != r);
        return 0;
    }

  private:
    int _n, size, log;
    std::vector<S> d;
    std::vector<F> lz;

    void update(int k) { d[k] = op(d[2 * k], d[2 * k + 1]); }
    void all_apply(int k, F f) {
        d[k] = mapping(f, d[k]);
        if (k < size) lz[k] = composition(f, lz[k]);
    }
    void push(int k) {
        all_apply(2 * k, lz[k]);
        all_apply(2 * k + 1, lz[k]);
        lz[k] = id();
    }
};

}  // namespace atcoder


using namespace std;

using ll = long long int;

inline void fast_io() { ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr); };
template<typename T> inline vector<T> fetch_vec(int sz) { vector<T> ret(sz); for (auto& elem : ret) cin >> elem; return ret; }

int H, W;
vector<int> A,B;
void input(){
    fast_io();
    cin >> H >> W;
    for (int i = 0; i < H; i++)
    {
        int a, b; cin >> a >> b;
        a--, b--;
        A.push_back(a);
        B.push_back(b);
    }
}


ll INF = (ll)1e9;
struct S{
    ll x, i;
};
S op(S x, S y){return S{min(x.x, y.x), min(x.i, y.i)};}
S e(){return S{INF, INF};}
struct F
{
    ll a,b,c;
};
S mapping(F f, S x){return S{f.a*x.x +  f.b*x.i + f.c, x.i};}
F composition(F f, F g){return F{f.a*g.a, f.b+f.a*g.b, f.c+f.a*g.c};}
F id(){return F{1,0,0};}

int solve(){
    // データ構造で殴る！きもちいいい！！
    vector<S> Init(W);
    for (int j = 0; j < W; j++) Init[j] = S{0, j};
    
    atcoder::lazy_segtree<S, op, e, F, mapping, composition, id> seg(Init);
    vector<ll> Ans;
    for (int h = 0; h < H; h++)
    {
        ll a = 0;
        if(A[h] > 0) a = seg.prod(A[h] - 1, A[h]).x;

        if(A[h]==0 || a>=INF){
            seg.apply(A[h], B[h]+1, F{0,0,INF});
            Ans.push_back(h+1+seg.all_prod().x);
        }
        else{
            seg.apply(A[h], B[h]+1, F{0,1,a-(A[h]-1)});
            Ans.push_back(h+1+seg.all_prod().x);
        }
    }
    for(auto x:Ans) cout << ((x>=INF)?-1:x) << "\n";
    return 0;
}

int TLEsolve(){
    vector<ll> cost(W,0);
    vector<ll> Ans;
    for (int i = 0; i < H; i++)
    {
        for (int j = 0; j < W; j++)
        {
            if(A[i] <= j && j <= B[i]){
                cost[j] = 1e6;
            }
            else{
                cost[j]++;
            }
            if(j) cost[j] = min(cost[j], cost[j-1] + 1);
        }
        int ans = *min_element(cost.begin(),cost.end());
        if(ans >= 1e6) ans = -1;
        // cout << ans << endl;
        Ans.push_back(ans);
    }
    for(auto x:Ans) cout << x << "\n";
    return 0;   
}

int main()
{
    input();
    solve();
    return 0;
}

Measured memory_bytes: 24300