void main(){
  import std.stdio, std.string, std.conv, std.algorithm;

  long d; int q; rd(d, q);
  import std.typecons;
  alias Query=Tuple!(long, "a", long, "b");
  auto queries=new Query[](q);
  long[] vals;
  foreach(i; 0..q){
    long a, b; rd(a, b);
    queries[i]=Query(a, b+1);
    vals~=queries[i].a;
    vals~=queries[i].b;
  }
  sort(vals);
  int[long] map;
  foreach(val; vals){
    if((val in map)==null) map[val]=map.length.to!(int);
  }
  long[int] rev;
  foreach(long k; map.keys){
    rev[map[k]]=k;
  }
  // writeln(map);
  
  auto tree=new SquareRootDecompotision(map.length.to!(int));
  long mx=0;
  foreach(query; queries){
    int l=map[query.a], r=map[query.b];
    tree.merge(l, r);
    long ol=rev[tree.getLeft(l)], or=rev[tree.getRight(l)];
    mx=max(mx, or-ol);
    // writeln(ol, " ", or);
    writeln(mx);
    // tree.show;
  }
}

class SquareRootDecompotision{
  int D=1;
  int[] st, ed;
  int[] buc_st, buc_ed;
  import std.algorithm;
  this(int n){
    while(D*D<n) D++;
    st.length=ed.length=(D*D);
    buc_st.length=buc_ed.length=D;
    foreach(int i; 0..(D*D)) st[i]=ed[i]=i;
    fill(buc_st, -1);
    fill(buc_ed, -1);
  }

  void merge(int left, int right){
    int l=min(left, st[left]), r=max(right, ed[right]);
    if(buc_st[left/D]>=0) chmin(l, buc_st[left/D]);
    if(buc_st[right/D]>=0) chmax(r, buc_ed[right/D]);
    if(left-1>=0){
      if(st[left-1]<ed[left-1]) chmin(l, st[left-1]);
      if(buc_st[(left-1)/D]>=0) chmin(l, buc_st[(left-1)/D]);
    }
    int bl=l/D, br=r/D;
    if(br-bl<=1){
      eachFill(l, r, l, r);
    }else{
      eachFill(l, (bl+1)*D, l, r);
      buc_st[(bl+1)..br]=l;
      buc_ed[(bl+1)..br]=r;
      eachFill(br*D, r, l, r);
    }
  }
  void eachFill(int tl, int tr, int l, int r){ // j in [tl, tr) st[j]<-l, ed[j]<-r
    push(tl/D); push(tr/D);
    // import std.stdio;
    // writeln(tl, " ", tr, " ", l, " ", r);
    foreach(int j; tl..tr) st[j]=l, ed[j]=r;
  }
  void push(int k){
    if(buc_st[k]>=0) st[k*D..(k+1)*D]=buc_st[k];
    if(buc_ed[k]>=0) ed[k*D..(k+1)*D]=buc_ed[k];
    buc_st[k]=buc_ed[k]=-1;
  }
  int getLeft(int i){
    int l=i;
    if(buc_st[i/D]>=0){
      l=min(l, buc_st[i/D]);
    }else{
      l=min(l, st[i]);
    }
    return l;
  }
  int getRight(int i){
    int r=i;
    if(buc_ed[i/D]>=0){
      r=max(r, buc_ed[i/D]);
    }else{
      r=max(r, ed[i]);
    }
    return r;
  }

  void show(){
    import std.stdio;
    writeln(st);
    writeln(buc_st);
    writeln(ed);
    writeln(buc_ed);
  }
}

void chmin(T)(ref T l, T r){if(l>r)l=r;}
void chmax(T)(ref T l, T r){if(l<r)l=r;}

void rd(Type...)(ref Type x){
  import std.stdio, std.string, std.conv;
  auto l=readln.split;
  assert(l.length==x.length);
  foreach(i, ref e; x){
    e=l[i].to!(typeof(e));
  }
}