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#include <cstdio>

#include "message.h"
#include "krazki.h"

const long long INF = 0x7FFFFFFFFFFFFFFFuLL;
int nodes, me, height, discs;

long long HoleDiam(int i) {
  ++i;
  return (i == height) ? 0 : HoleDiameter(i);
}

long long DiscDiam(int i) {
  ++i;
  return DiscDiameter(i);
}

int main (void) {
  nodes = NumberOfNodes();
  me = MyNodeId();

  height = PipeHeight();
  discs = NumberOfDiscs();

  ++height; // HoleDiam returns 0 at bottom

  // Cannot handle too many nodes.
  // Every pipe slice must be non-empty.
  if (nodes > height) nodes = height;

  if (me >= nodes) return 0;

  // pipe cleaner

  int pipe_ofs[nodes + 1];
  for (int i = 0; i <= nodes; ++i) {
    pipe_ofs[i] = height * i / nodes;
  }

  int p_lo = pipe_ofs[me];
  int p_hi = pipe_ofs[me + 1];
  int p_cnt = p_hi - p_lo;
  long long PD[p_cnt];
  long long min_d = INF;
  for (int i = p_lo; i < p_hi; ++i) {
    long long d = HoleDiam(i);
    PD[i - p_lo] = d;
    if (d < min_d) min_d = d;
  }

  for (int i = 0; i < nodes; ++i) {
    PutLL(i, min_d);
    Send(i);
  }

  long long PminD[nodes];
  for (int i = 0; i < nodes; ++i) {
    int j = Receive(i);
    PminD[j] = GetLL(j);
  }

  min_d = INF;
  for (int i = 0; i < nodes; ++i) {
    if (PminD[i] < min_d) min_d = PminD[i];
    PminD[i] = min_d;
  }
  min_d = me ? PminD[me - 1] : INF;

  for (int i = 0; i < p_cnt; ++i) {
    if (PD[i] > min_d) PD[i] = min_d;
    min_d = PD[i];
  }

  // disc cleaner

  int disc_ofs[nodes + 1];
  for (int i = 0; i <= nodes; ++i) {
    disc_ofs[i] = discs * i / nodes;
  }

  int d_lo = disc_ofs[me];
  int d_hi = disc_ofs[me + 1];
  int d_cnt = d_hi - d_lo;
  long long DD[p_cnt];
  long long max_d = 0;
  for (int i = d_lo; i < d_hi; ++i) {
    long long d = DiscDiam(i);
    DD[i - d_lo] = d;
    if (d > max_d) max_d = d;
  }

  for (int i = 0; i < nodes; ++i) {
    PutLL(i, max_d);
    Send(i);
  }

  long long DmaxD[nodes];
  for (int i = 0; i < nodes; ++i) {
    int j = Receive(i);
    DmaxD[j] = GetLL(j);
  }

  max_d = 0;
  for (int i = 0; i < nodes; ++i) {
    if (DmaxD[i] > max_d) max_d = DmaxD[i];
    DmaxD[i] = max_d;
  }
  max_d = me ? DmaxD[me - 1] : 0;

  for (int i = 0; i < d_cnt; ++i) {
    if (DD[i] < max_d) DD[i] = max_d;
    max_d = DD[i];
  }

  // cleaning done

  // find...
  long long found;
  int place;

  for (int i = 0; i < nodes; ++i) {
    // binsearch in DD[0 .. d_cnt);
    long long find = PminD[i] + 1;
    int lo = 0;
    int hi = d_cnt;
    while (lo < hi) {
      int mid = (lo + hi) / 2;
      if (DD[mid] < find)
        lo = mid + 1;
      else
        hi = mid;
    };

    int where = d_lo + lo;
    if (where >= d_hi) where = 0x7FFFFFFF;

    // Node i cares about this slice
    PutInt(i, where);
    Send(i);

    if (me != i) continue;

    int located = 0x7FFFFFFF;
    for (int j = 0; j < nodes; ++j) {
      Receive(j);
      int v = GetInt(j);
      if (v < located) located = v;
    }

    found = find;
    place = located;
  }

  if (me + 1 < nodes) {
    PutInt(me + 1, place);
    Send(me + 1);
  }

  int place_end;

  if (!me) {
    place_end = 0x7FFFFFFF;
  } else {
    Receive(me - 1);
    place_end = GetInt(me - 1);
  }

  if (place > discs) place = discs;
  if (place_end > discs) place_end = discs;

  int used = 0;
  int spare = 0;
  int p_where = p_hi - 1;

  while (place < place_end) {
    long long discdiam = DiscDiam(place);
    while ((p_where >= p_lo) && (discdiam > PD[p_where - p_lo])) {
      --p_where;
      ++spare;
    }
    if (p_where >= p_lo) {
      --p_where;
      ++used;
      ++place;
    } else break;
  }
  PutInt(0, used);
  PutInt(0, spare);
  PutInt(0, place_end - place);
  PutInt(0, p_where + 1 - p_lo);
  Send(0);

  if (me) return 0;

  int USED[nodes];
  int SPARE[nodes];
  int LEFT[nodes];
  int DEPTH[nodes];

  for (int i = 0; i < nodes; ++i) {
    Receive(i);
    USED[i] = GetInt(i);
    SPARE[i] = GetInt(i);
    LEFT[i] = GetInt(i);
    DEPTH[i] = GetInt(i);
  }

  int deep = 0;
  for (int i = 0; i < nodes; ++i) {
    int j = nodes - 1 - i;

    // spare cancels out -deep
    if (deep < 0) {
      deep += SPARE[j];
      if (deep > 0) deep = 0;
    }

    // +deep useless if stuff was used
    if (USED[j]) if (deep > 0) deep = 0;

    deep += DEPTH[j];

    // +deep useless if stuff was left
    if (LEFT[j]) if (deep > 0) deep = 0;

    deep -= LEFT[j];
  }

  if (deep < 0)
    printf("0\n");
  else
    printf("%d\n", deep + 1);
}