#include <cstdio>#include <cstring>#include <algorithm>#include <map>#include <set>#include <bitset>#include <queue>#include <stack>#include <string>#include <iostream>#include <cmath>#include <climits>using namespace std;const int maxn = 111111;const int INF = 0xfffffff;int sum1[maxn];int sum2[maxn];int n;int a[maxn];int erfen1(int l,int r,int key){    int ans = INF;    int k = l;    while(l<=r){        int mid=(l+r)>>1;        if(sum1[mid]-sum1[k-1] == key) ans=mid;        if(sum1[mid]-sum1[k-1] >= key) r = mid-1;        else l = mid+1;    }    return ans;}int erfen2(int l,int r,int key){    int ans = INF;    int k = l;    while(l<=r){        int mid=(l+r)>>1;        if(sum2[mid] - sum2[k-1]==key) ans = mid;        if(sum2[mid] - sum2[k-1]>=key) r = mid-1;        else l = mid+1;    }    return ans;}int judge(int t){    int ans1 = 0;int ans2 = 0;    int l = 1;    while(l<=n){        int t1 = erfen1(l,n,t);        int t2 = erfen2(l,n,t);        l = min(t1,t2) + 1;        if(l>n+1) return 0;        if(t1==t2&&t1==INF) continue;        if(t1<t2) ans1++;        else ans2++;        if(l-1==n){            if(ans1>ans2&&t1>t2) return 0;            if(ans2>ans1&&t2>t1) return 0;        }    }    if(ans1==ans2) return 0;    return ans1>ans2? ans1:ans2;}struct Node{    int x;int y;};int cmp(const Node &a,const Node & b){    return a.x<b.x;}vector<Node > q;int main(){    cin>>n;    memset(sum2,0,sizeof(sum2));    memset(sum1,0,sizeof(sum1));    for(int i = 1;i<=n;i++){        scanf("%d",&a[i]);        if(a[i]==1) sum1[i] = 1;        else sum2[i] = 1;    }    for(int i =1;i<=n;i++)        sum1[i]+=sum1[i-1],sum2[i]+=sum2[i-1];    for(int t = 1;t<=n;t++){        int gg = judge(t);        if(gg==0) continue;        Node k ; k.x = gg; k.y = t;        q.push_back(k);    }    sort(q.begin(),q.end(),cmp);    printf("%d\n",q.size());    for(int i = 0;i<q.size();i++)        printf("%d %d\n",q[i].x,q[i].y);    return 0;}