1 #include<bits/stdc++.h>
 2 #define lowbit(x) x&(-x) 
 3 #define LL long long 
 4 #define N 200005
 5 #define M 1000005
 6 #define mod 2147483648LL
 7 #define inf 0x7ffffffff
 8 using namespace std;
 9 inline int ra()
10 {
11     int x=0,f=1; char ch=getchar();
12     while (ch<‘0‘ || ch>‘9‘){if (ch==‘-‘) f=-1; ch=getchar();}
13     while (ch>=‘0‘ && ch<=‘9‘){x=x*10+ch-‘0‘; ch=getchar();}
14     return x*f;
15 }
16 int a[1005];
17 struct node{
18     int x,y;
19 }ans[1005];
20 int cnt;
21 int main()
22 {
23     int n=ra(),start=1;
24     bool flag=0;
25     for (int i=1; i<=n; i++)
26     {
27         int x=ra();
28         if (x!=0) a[i]=x,flag=1;
29     }
30     if (!flag) 
31     {
32         cout<<"NO";
33         return 0;
34     }
35     cout<<"YES"<<endl;
36     if (a[1]==0)
37     {
38         for (int i=1; i<=n; i++)
39             if (a[i]!=0) 
40             {
41                 for (int j=i+1; j<=n; j++)
42                     if (a[j]!=0 || j==n) 
43                     {
44                         ans[++cnt].x=1;
45                         ans[cnt].y=j-1;
46                         start=j;
47                         break;
48                     }
49                 break;
50             }
51         int last=start;
52         for (int i=last; i<=n; i++)
53         {
54             if (i==n && a[i]==0)
55                 ans[cnt].y=n;
56             if (a[i]!=0)
57             {
58                 ans[++cnt].x=start;
59                 ans[cnt].y=i;
60                 start=i+1;
61             }
62         }
63     }
64     else 
65     {
66         int last=start;
67         for (int i=last; i<=n; i++)
68         {
69             if (i==n && a[i]==0)
70                 ans[cnt].y=n;
71             if (a[i]!=0)
72             {
73                 ans[++cnt].x=start;
74                 ans[cnt].y=i;
75                 start=i+1;
76             }
77         }
78     }
79     cout<<cnt<<endl;
80     for (int i=1; i<=cnt; i++)
81         cout<<ans[i].x<<" "<<ans[i].y<<endl;
82     return 0;
83 }