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#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <vector>
#include <string>
#include <map>
#include <set>
#include <cassert>
using namespace std;
#define rep(i,a,n) for (int i=a;i<n;i++)
#define per(i,a,n) for (int i=n-1;i>=a;i--)
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
typedef vector<int> VI;
typedef long long ll;
typedef pair<int,int> PII;
const ll mod=1000000007;
ll powmod(ll a,ll b) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
// head

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

const int N=2510000;

int n,T,block,myid;
void output(int id,ll v) {
	if (id>=0&&id<T) {
		PutLL(id,v);
		Send(id);
	}
}
ll a[N];
int main() {
	n=PipeHeight(),T=NumberOfNodes(),block=(n+T-1)/T,myid=MyNodeId();
	int l=block*myid+1,r=min(block*(myid+1),n);
	int m=r-l+1;
	rep(i,1,m+1) a[i]=HoleDiameter(i+l-1);
	// deliver prefix min
	rep(i,2,m+1) a[i]=min(a[i],a[i-1]);
	ll ph=1ll<<60;
	if (myid!=0) {
		Receive(myid-1);
		ph=min(ph,GetLL(myid-1));
	}
	output(myid+1,min(ph,a[m]));
//	printf("%d %lld\n",myid,ph);
	//process
	ll p=0,q=NumberOfDiscs();
	if (myid==T-1) {
		p=q;
	} else {
		Receive(myid+1);
		p=GetLL(myid+1);
	}
//	printf("%d %lld\n",myid,p);
	if (p==0) {
		output(myid-1,0);
		return 0;
	}
	ll v=DiscDiameter(q-p+1);
	per(i,1,m+1) {
		if (myid!=0&&v>ph) {
			output(myid-1,p);
			return 0;
		}
		while (i&&a[i]<v) i--;
		if (i==0) break;
		if (p==1) {
			printf("%d\n",l+i-1);
			output(myid-1,0);
			return 0;
		}
		--p; v=DiscDiameter(q-p+1);
	}
	if (myid==0) puts("0");
	else output(myid-1,p);
}