#include<iostream>

 #include<algorithm>

 #include<cstring>

 #include<cstdio>

 #include<sstream>

 #include<vector>

 #include<stack>

 #include<queue>

 #include<cmath>

 #include<map>

 using namespace std;

 typedef long long ll;

 typedef pair<int,int> pll;

 const int INF = 0x3f3f3f3f;

 const int maxn=+;

 int n;

 int a[maxn];

 struct node

 {

     int l, r;

 }ans[maxn];

 int main()

 {

     //freopen("in.txt","r",stdin);

     while(~scanf("%d",&n))

     {

         int cnt=;

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

             scanf("%d",&a[i]);

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

              if(a[i]!=)  cnt++;

         if(cnt==)   {puts("NO");continue;}

         int i=;

         cnt=;

         while(i<=n)

         {

             ans[cnt].l=i;

             while(a[i]==)  i++;

             while(i<n && a[i+]==)   i++;

             ans[cnt].r=i;

             i++;

             cnt++;

         }

         puts("YES");

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

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

         {

             printf("%d %d\n", ans[i].l, ans[i].r);

         }

     }

     return ;

 }