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

#include <cstdio>
#include <cstdlib>

typedef long long int64;

int main () {
	int node_id = MyNodeId();
	int nodes = NumberOfNodes();
	int pipe = PipeHeight();
	int discs = NumberOfDiscs();
	if ((discs > pipe) || (DiscDiameter(discs) > HoleDiameter(1))) {
		if (!node_id) {
			printf("0\n");
		}
		return 0;
	}
	int pipe_nodes = nodes;
	if (pipe < pipe_nodes) {
		pipe_nodes = pipe;
	}
	int pipe_starts[pipe_nodes];
	int pipe_ends[pipe_nodes];
	int seg_length = pipe / nodes;
	int remaining = pipe - seg_length * nodes;
	int at = 1;
	for (int i = 0; i < pipe_nodes; ++i) {
		pipe_starts[i] = at;
		at += seg_length;
		if (remaining) {
			++at;
			--remaining;
		}
		pipe_ends[i] = at - 1;
	}
	int64 min_diam;
	if (node_id < pipe_nodes - 1) {
		min_diam = HoleDiameter(pipe_starts[node_id]);
		for (int i = pipe_starts[node_id] + 1; i <= pipe_ends[node_id]; ++i) {
			int64 diam = HoleDiameter(i);
			if (diam < min_diam) {
				min_diam = diam;
			}
		}
		if (node_id) {
			PutLL(0, min_diam);
			Send(0);
		}
	}
	int pipe_bounds[pipe_nodes];
	if (node_id == 0) {
		pipe_bounds[0] = HoleDiameter(1);
		pipe_bounds[1] = min_diam;
		int64 min_so_far = min_diam;
		for (int i = 1; i < pipe_nodes - 1; ++i) {
			Receive(i);
			int64 rcv_min = GetLL(i);
			if (rcv_min < min_so_far) {
				min_so_far = rcv_min;
			}
			pipe_bounds[i + 1] = min_so_far;
		}
		if (nodes > 1) {
			for (int i = 0; i < pipe_nodes; ++i) {
				PutLL(1, pipe_bounds[i]);
			}
			Send(1);
		}
	}
	else {
		Receive(node_id - 1);
		for (int i = 0; i < pipe_nodes; ++i) {
			pipe_bounds[i] = GetLL(node_id - 1);
		}
		if (node_id < nodes - 1) {
			for (int i = 0; i < pipe_nodes; ++i) {
				PutLL(node_id + 1, pipe_bounds[i]);
			}
			Send(node_id + 1);
		}
	}
	int disc_nodes = nodes;
	if (discs < disc_nodes) {
		disc_nodes = discs;
	}
	int disc_starts[disc_nodes];
	int disc_ends[disc_nodes];
	seg_length = discs / nodes;
	remaining = discs - seg_length * nodes;
	at = 1;
	for (int i = 0; i < disc_nodes; ++i) {
		disc_starts[i] = at;
		at += seg_length;
		if (remaining) {
			++at;
			--remaining;
		}
		disc_ends[i] = at - 1;
	}
	int64 max_diam;
	int64* disc_diams;
	if (node_id < disc_nodes) {
		disc_diams = (int64*)malloc((disc_ends[node_id] - disc_starts[node_id] + 4) * sizeof(int64));
		max_diam = DiscDiameter(disc_starts[node_id]);
		disc_diams[0] = max_diam;
		for (int i = disc_starts[node_id] + 1; i <= disc_ends[node_id]; ++i) {
			int64 diam = DiscDiameter(i);
			disc_diams[i - disc_starts[node_id]] = diam;
			if (diam > max_diam) {
				max_diam = diam;
			}
		}
		if (node_id && (node_id < disc_nodes - 1)) {
			PutLL(0, max_diam);
			Send(0);
		}
	}
	int64 diam_bound = 0;
	if (node_id == 0) {
		int64 bound = max_diam;
		for (int i = 1; i < disc_nodes - 1; ++i) {
			Receive(i);
			int64 rcv_max = GetLL(i);
			PutLL(i, bound);
			Send(i);
			if (rcv_max > bound) {
				bound = rcv_max;
			}
		}
		if (disc_nodes > 1) {
			PutLL(disc_nodes - 1, bound);
			Send(disc_nodes - 1);
		}
	}
	else if (node_id < disc_nodes) {
		Receive(0);
		diam_bound = GetLL(0);
	}
	if (node_id < disc_nodes) {
		for (int i = 0; i <= disc_ends[node_id] - disc_starts[node_id]; ++i) {
			if (disc_diams[i] > diam_bound) {
				diam_bound = disc_diams[i];
			}
			else {
				disc_diams[i] = diam_bound;
			}
		}
	}
	int pipe_seg = 0;
	if (node_id < disc_nodes) {
		while (1) {
			if (pipe_seg == pipe_nodes - 1) {
				break;
			}
			if (HoleDiameter(pipe_starts[pipe_seg + 1]) < disc_diams[disc_ends[node_id] - disc_starts[node_id]]) {
				break;
			}
			if (pipe_bounds[pipe_seg + 1] < disc_diams[disc_ends[node_id] - disc_starts[node_id]]) {
				break;
			}
			++pipe_seg;
		}
		int64 bound = pipe_bounds[pipe_seg];
		int top_idx = pipe_starts[pipe_seg];
		while (1) {
			int64 diam = HoleDiameter(top_idx);
			if (bound < diam) {
				diam = bound;
			}
			if (diam < disc_diams[disc_ends[node_id] - disc_starts[node_id]]) {
				--top_idx;
				break;
			}
			if (diam < bound) {
				bound = diam;
			}
			if (top_idx >= pipe - 1) {
				break;
			}
			++top_idx;
		}
		int64* holes = (int64*)malloc((disc_ends[node_id] - disc_starts[node_id] + 4) * sizeof(int64));
		int idx = top_idx;
		int length = 0;
		for (int i = 0; i < disc_ends[node_id] - disc_starts[node_id] + 2; ++i) {
			int64 diam = HoleDiameter(idx);
			if (bound < diam) {
				diam = bound;
			}
			holes[length] = diam;
			++length;
			if (diam < bound) {
				bound = diam;
			}
			++idx;
			if (idx > pipe) {
				break;
			}
		}
		int height = 0;
		int disc_idx = 0;
		while (1) {
			int64 pipe_diam = holes[0];
			if (height < length) {
				pipe_diam = holes[length - height - 1];
			}
			if (disc_diams[disc_idx] <= pipe_diam) {
				++disc_idx;
				if (disc_idx == disc_ends[node_id] - disc_starts[node_id] + 1) {
					break;
				}
			}
			++height;
		}
		int top_index = top_idx - height + length - 1;
		if (node_id) {
			PutLL(0, top_index);
			Send(0);
		}
		else {
			for (int i = 1; i < disc_nodes; ++i) {
				Receive(i);
				int64 new_top = GetLL(i);
				int64 min_top = top_index - (disc_ends[i] - disc_starts[i] + 1);
				if (new_top > min_top) {
					new_top = min_top;
				}
				top_index = new_top;
			}
			printf("%d\n", top_index <= 0 ? 0 : top_index);
		}
	}
	return 0;
}