#include <bits/stdc++.h>
using namespace std;
template <typename T, typename U>
inline void smin(T &a, U b) {
  if (a > b) a = b;
}
template <typename T, typename U>
inline void smax(T &a, U b) {
  if (a < b) a = b;
}
template <class T>
inline void gn(T &first) {
  char c, sg = 0;
  while (c = getchar(), (c > '9' || c < '0') && c != '-')
    ;
  for ((c == '-' ? sg = 1, c = getchar() : 0), first = 0; c >= '0' && c <= '9';
       c = getchar())
    first = (first << 1) + (first << 3) + c - '0';
  if (sg) first = -first;
}
template <class T>
inline void print(T first) {
  if (first < 0) {
    putchar('-');
    return print(-first);
  }
  if (first < 10) {
    putchar('0' + first);
    return;
  }
  print(first / 10);
  putchar(first % 10 + '0');
}
template <class T, class T1>
inline void gn(T &first, T1 &second) {
  gn(first);
  gn(second);
}
template <class T, class T1, class T2>
inline void gn(T &first, T1 &second, T2 &z) {
  gn(first);
  gn(second);
  gn(z);
}
template <class T>
inline void println(T first) {
  print(first);
  putchar('\n');
}
template <class T>
inline void printsp(T first) {
  print(first);
  putchar(' ');
}
template <class T1, class T2>
inline void print(T1 x1, T2 x2) {
  printsp(x1), println(x2);
}
template <class T1, class T2, class T3>
inline void print(T1 x1, T2 x2, T3 x3) {
  printsp(x1), printsp(x2), println(x3);
}
template <class T1, class T2, class T3, class T4>
inline void print(T1 x1, T2 x2, T3 x3, T4 x4) {
  printsp(x1), printsp(x2), printsp(x3), println(x4);
}
template <class T>
inline void eprint(T first) {
  cerr << "--------> " << first << endl;
}
template <class T1, class T2>
inline void eprint(T1 first, T2 second) {
  cerr << "--------> " << first << ' ' << second << endl;
}
template <class T1, class T2, class T3>
inline void eprint(T1 first, T2 second, T3 z) {
  cerr << " -------> " << first << ' ' << second << ' ' << z << endl;
}
template <class T1, class T2, class T3, class T4>
inline void eprint(T1 first, T2 second, T3 z, T4 w) {
  cerr << " -------> " << first << ' ' << second << ' ' << z << ' ' << w
       << endl;
}
int power(int a, int b, int m, int ans = 1) {
  for (; b; b >>= 1, a = 1LL * a * a % m)
    if (b & 1) ans = 1LL * ans * a % m;
  return ans;
}
int a[100011];
int n;
int cnt[100011][2];
vector<pair<int, int> > ans;
int main() {
  cin >> n;
  for (int i = 1; i <= n; i++) {
    gn(a[i]), a[i]--;
    cnt[i][0] = cnt[i - 1][0];
    cnt[i][1] = cnt[i - 1][1];
    cnt[i][a[i]]++;
  }
  for (int k = 1; k <= n; k++) {
    int now = 0, nxt;
    int s = 0, t = 0;
    while (now < n) {
      int st = now, ed = n + 1;
      while (ed > st + 1) {
        int mid = st + ed >> 1;
        if (max(cnt[mid][0] - cnt[now][0], cnt[mid][1] - cnt[now][1]) >= k)
          ed = mid;
        else
          st = mid;
      }
      if (cnt[ed][0] - cnt[now][0] == k)
        s++;
      else
        t++;
      now = ed;
    }
    if (s >= t and a[n]) continue;
    if (s <= t and a[n] == 0) continue;
    if (now == n and s != t) ans.push_back(pair<int, int>(max(s, t), k));
  }
  sort(ans.begin(), ans.end());
  println(((int)ans.size()));
  for (int i = 0; i < ((int)ans.size()); i++)
    print(ans[i].first, ans[i].second);
  return 0;
}
