#include <bits/stdc++.h>
//#define DEBUG
#include "gap.h"
using namespace std;
typedef long long LL;
long long findGap(int op, int N)
{
if(op == 1)
{
LL st = 0, dr = 1e18;
vector<LL> v;
for(int i = 1; i <= N; i += 2)
{
LL vl, vr;
MinMax(st, dr, &vl, &vr);
v.push_back(vl);
if(i + 1 <= N) v.push_back(vr);
st = vl + 1;
dr = vr - 1;
}
sort(v.begin(), v.end());
LL ans = 0;
for(int i = 1; i < v.size(); i++)
ans = max(ans, v[i] - v[i - 1]);
return ans;
}
else if(op == 2)
{
LL st, dr;
MinMax(0LL, LL(1e18), &st, &dr);
LL ans = 0;
LL lgt = ceil( (long double)(dr - st) / (long double)(N - 1) );
LL rgt = st;
for(LL lft = st; lft < dr; lft += lgt)
{
LL x, y;
MinMax(lft, lft + lgt - 1, &x, &y);
if(x == -1) continue;
ans = max(ans, x - rgt);
rgt = y;
}
ans = max(ans, dr - rgt);
return ans;
}
return 0LL;
}
#ifdef DEBUG
#include <stdio.h>
#include <stdlib.h>
static void my_assert(int k){ if (!k) exit(1); }
static int subtask_num, N;
static long long A[100001];
static long long call_count;
void MinMax(long long s, long long t, long long *mn, long long *mx)
{
int lo = 1, hi = N, left = N+1, right = 0;
my_assert(s <= t && mn != NULL && mx != NULL);
while (lo <= hi){
int mid = (lo+hi)>>1;
if (A[mid] >= s) hi = mid - 1, left = mid;
else lo = mid + 1;
}
lo = 1, hi = N;
while (lo <= hi){
int mid = (lo+hi)>>1;
if (A[mid] <= t) lo = mid + 1, right = mid;
else hi = mid - 1;
}
if (left > right) *mn = *mx = -1;
else{
*mn = A[left];
*mx = A[right];
}
if (subtask_num == 1) call_count++;
else if (subtask_num == 2) call_count += right-left+2;
}
int main()
{
FILE *in = fopen("1.in", "r"), *out = stdout;
my_assert(2 == fscanf(in, "%d%d", &subtask_num, &N));
my_assert(1 <= subtask_num && subtask_num <= 2);
my_assert(2 <= N && N <= 100000);
for (int i=1;i<=N;i++) my_assert(1 == fscanf(in, "%lld", A+i));
for (int i=1;i<N;i++) my_assert(A[i] < A[i+1]);
fprintf(out, "%lld\n", findGap(subtask_num, N));
fprintf(out, "%lld\n", call_count);
}
#endif
