#define CPP17
#include <limits>
#include <initializer_list>
#include <utility>
#include <bitset>
#include <tuple>
#include <type_traits>
#include <functional>
#include <string>
#include <array>
#include <deque>
#include <list>
#include <queue>
#include <stack>
#include <vector>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <iterator>
#include <algorithm>
#include <complex>
#include <random>
#include <numeric>
#include <iostream>
#include <iomanip>
#include <sstream>
#include <regex>
#include <cassert>
#include <cstddef>
#ifdef CPP17
#include <variant>
#endif

#define endl codeforces

#define ALL(v) std::begin(v), std::end(v)
#define ALLR(v) std::rbegin(v), std::rend(v)

using ll = std::int64_t;
using ull = std::uint64_t;
using pii = std::pair<int, int>;
using tii = std::tuple<int, int, int>;
using pll = std::pair<ll, ll>;
using tll = std::tuple<ll, ll, ll>;
using size_type = ssize_t;
template <typename T> using vec = std::vector<T>;
template <typename T> using vvec = vec<vec<T>>;

template <typename T> const T& var_min(const T &t) { return t; }
template <typename T> const T& var_max(const T &t) { return t; }
template <typename T, typename... Tail> const T& var_min(const T &t, const Tail&... tail) { return std::min(t, var_min(tail...)); }
template <typename T, typename... Tail> const T& var_max(const T &t, const Tail&... tail) { return std::max(t, var_max(tail...)); }
template <typename T, typename... Tail> void chmin(T &t, const Tail&... tail) { t = var_min(t, tail...); }
template <typename T, typename... Tail> void chmax(T &t, const Tail&... tail) { t = var_max(t, tail...); }

template <typename T, std::size_t Head, std::size_t... Tail> 
struct multi_dim_array { using type = std::array<typename multi_dim_array<T, Tail...>::type, Head>; };

template <typename T, std::size_t Head> 
struct multi_dim_array<T, Head> { using type = std::array<T, Head>; };

template <typename T, std::size_t... Args> using mdarray = typename multi_dim_array<T, Args...>::type;

#ifdef CPP17
template <typename T, typename F, typename... Args> 
void fill_seq(T &t, F f, Args... args) { 
    if constexpr (std::is_invocable<F, Args...>::value) { 
        t = f(args...); 
    } else { 
        for (size_type i = 0; i < t.size(); i++) fill_seq(t[i], f, args..., i); 
    } 
}
#endif

template <typename T> vec<T> make_v(size_type sz) { return vec<T>(sz); }

template <typename T, typename... Tail> 
auto make_v(size_type hs, Tail&&... ts) { 
    auto v = std::move(make_v<T>(std::forward<Tail>(ts)...)); 
    return vec<decltype(v)>(hs, v); 
}

namespace init__ { 
struct InitIO { 
    InitIO() { 
        std::cin.tie(nullptr); 
        std::ios_base::sync_with_stdio(false); 
        std::cout << std::fixed << std::setprecision(30); 
    } 
} init_io; 
}
template <typename T>
T ceil_pow2(T bound) {
    T ret = 1;
    while (ret < bound) ret *= 2;
    return ret;
}
template <typename T>
T ceil_div(T a, T b) { return a / b + !!(a % b); }
#define CPP17


const ll inf = 5e15;

int main() {
    ll h, w;
    std::cin >> h >> w;
    vec<pll> lrv(h);
    for (auto &[ a, b ] : lrv) {
        std::cin >> a >> b;
        a--;
    }

    std::set<pll> set;
    std::multiset<ll> dists;
    for (ll i = 0; i < w; i++) {
        set.emplace(i, i);
        dists.insert(0);
    }

    auto remove_set_ele = [&](pll p) {
        auto [ r, l ] = p;
        ll d = r - l;
        auto ite = dists.find(d);
        dists.erase(ite);
        set.erase(p);
    };

    auto add_set_ele = [&](pll p) {
        auto [ r, l ] = p;
        ll d = r - l;
        dists.insert(d);
        set.insert(p);
    };

    for (ll i = 0; i < h; i++) {
        auto [ l, r ] = lrv[i];
        auto ite = set.lower_bound(pll(l, -1));
        ll maxl = -inf;
        vec<pll> rmv;
        for (; ite != set.end() && ite->first < r; ite = std::next(ite)) {
            chmax(maxl, ite->second);
            rmv.push_back(*ite);
        }
        for (auto e : rmv) remove_set_ele(e);
        if (r == w) r = 2 * inf;
        add_set_ele(pll(r, maxl));
        ll ans = *dists.begin();
        ans += i + 1;
        if (inf <= ans) ans = -1;
        std::cout << ans << "\n";
    }
    return 0;
}


Measured memory_bytes: 28252