#pragma GCC target("avx2,avx")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
using namespace std;
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
//using namespace __gnu_pbds;
//using i128 = __int128_t;
using ll = long long;
using ull = unsigned long long;
using pii = pair<int, int>;
using pll = pair<long long, long long>;
#define rep(i, n) for(int i = 0; i < (n); ++i)
#define all(x) (x).begin(),(x).end()
constexpr char ln = '\n';
constexpr long long MOD = 1000000007;
//constexpr long long MOD = 998244353;
template<class T1, class T2> inline bool chmax(T1 &a, T2 b) {if (a < b) {a = b; return true;} return false;}
template<class T1, class T2> inline bool chmin(T1 &a, T2 b) {if (a > b) {a = b; return true;} return false;}
inline int topbit(int x) {return x == 0 ? -1 : 31-__builtin_clz(x);}
inline int topbit(long long x) {return x == 0 ? -1 : 63-__builtin_clzll(x);}
inline int botbit(int x) {return x == 0 ? 32 : __builtin_ctz(x);}
inline int botbit(long long x) {return x == 0 ? 64 : __builtin_ctzll(x);}
inline int popcount(int x) {return __builtin_popcount(x);}
inline int popcount(long long x) {return __builtin_popcountll(x);}
inline void print() {cout << "\n";}
template<class T>
inline void print(const vector<T> &v) {
    for (auto itr = v.begin(); itr != v.end(); ++itr) cout << *itr << " ";
    print();
}
template<class T, class... Args>
inline void print(const T &x, const Args &... args) {
    cout << x << " ";
    print(args...);
}
#ifdef MINATO_LOCAL
#define dump(x) cerr << __LINE__ << " : " << #x << " = " << (x) << endl;
inline void debug() {cerr << endl;}
template<class T>
inline void debug(const vector<T> &v) {
    for (auto itr = v.begin(); itr != v.end(); ++itr) cerr << *itr << " ";
    debug();
}
template<class T, class... Args>
inline void debug(const T &x, const Args &... args) {
    cerr << x << " ";
    debug(args...);
}
#else
#define dump(x) void(0)
inline void debug() {}
template<class T> inline void debug(const vector<T> &v) {}
template<class T, class... Args> inline void debug(const T &x, const Args &... args) {}
#endif
struct Fast_ios {Fast_ios() {cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(20);};} fast_ios;
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

int main() {
    int H,W; cin >> H >> W;
    vector<int> L(H),R(H);
    rep(i,H) cin >> L[i] >> R[i], --L[i];

    set<pii> dic;
    multiset<int> st;
    rep(i,W) dic.emplace(i,0);
    rep(i,W) st.emplace(0);
    rep(i,H) {
        if (st.empty()) {
            cout << -1 << ln;
            continue;
        }
        int ins_val = 1e9;
        if (R[i] < W) {
            auto it = dic.lower_bound(pii(R[i],1e9));
            if (it != dic.begin()) {
                --it;
                auto[id,d] = *it;
                if (id != R[i]) {
                    ins_val = it->second + R[i] - it->first;
                }
            }
        }
        auto it2 = dic.lower_bound(pii(L[i],-1));
        while (it2 != dic.end() and it2->first < R[i]) {
            auto[a,b] = *it2;
            st.erase(st.find(b));
            it2 = dic.erase(it2);
        }
        if (ins_val != 1e9) {
            st.emplace(ins_val);
            dic.emplace(pii(R[i],ins_val));
        }
        if (st.empty()) cout << -1 << ln;
        else cout << *st.begin()+i+1 << ln;
    }
}

Measured memory_bytes: 23472