#include <cstdio>

 #include <algorithm>

 #include <cmath>

 #include <cstring>

 #include <cstdlib>

 #include <ctime>

 #include <set>

 #include <map>

 using namespace std;

 const int maxn=;

 struct point

 {

     int x, y;

 };

 int n;

 int sum;

 int a[maxn], des[maxn];

 point ans[];

 void init()

 {

     scanf("%d", &n);

     a[]=; a[n+]=n+;

     for (int i=; i<=n; ++i) scanf("%d", &a[i]);

 }

 void rev(int le, int ri)

 {

     for (int i=le; i<=(ri+le)/; ++i)

         swap(a[i], a[ri-(i-le)]);

 }

 bool check()

 {

     for (int i=; i<=n; ++i)

         if (a[i]!=i) return false;

     return true;

 }

 void print(int step)

 {

     printf("%d\n", step);

     for (int i=step; i>; --i)

         printf("%d %d\n", ans[i].x, ans[i].y);

     exit();

 }

 void dfs(int k)

 {

     if (check()) print(k-);

     if (k>) return;

     for (int i=; i<n; ++i)

         for (int j=i+; j<=n; ++j)

             if (abs(a[i-]-a[j])== || abs(a[i]-a[j+])==)

             {

                 ans[k].x=i;

                 ans[k].y=j;

                 rev(i, j);

                 dfs(k+);

                 rev(i, j);

             }

 }

 int main()

 {

     freopen("input.txt", "r", stdin);

     freopen("output.txt", "w", stdout);

     init();

     dfs();

     return ;

 }