import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.complex, std.container, std.math, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }
real readReal() { return readToken.to!real; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }


long D;
int Q;
long[] A, B;

void main() {
  try {
    for (; ; ) {
      D = readLong();
      Q = readInt();
      A = new long[Q];
      B = new long[Q];
      foreach (q; 0 .. Q) {
        A[q] = readLong();
        B[q] = readLong() + 1;
      }
      
      alias P = Tuple!(long, long);
      auto set = new RedBlackTree!P;
      long ans;
      foreach (q; 0 .. Q) {
        long a = A[q], b = B[q];
        auto r = set.lowerBound(P(B[q], D));
        P[] rems;
        for (; !r.empty; r.popBack) {
          if (max(a, r.back[0]) <= min(b, r.back[1])) {
            rems ~= r.back;
            chmin(a, r.back[0]);
            chmax(b, r.back[1]);
          } else {
            break;
          }
        }
        foreach (p; rems) {
          set.removeKey(p);
        }
        set.insert(P(a, b));
        debug {
          writeln("set = ", set);
        }
        chmax(ans, b - a);
        writeln(ans);
      }
    }
  } catch (EOFException e) {
  }
}