#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define f(i,a,b) for(int i = a; i < b; i++)
#define fa(i,a,b) for(int i = a; i >= b; i--)
const int N = 1e5 + 5, M = 5e6 + 5;
int n;
ll a[N], b[N], s[N];
bool l[N], r[N], ans[M];
void print(){
int res = 0;
f(i,1,M) res += ans[i];
cout << res << "\n";
f(i,1,M) if(ans[i]) cout << i << "\n";
}
ll sum(int l, int r){
return s[r] - s[l-1];
}
int main(){
cin >> n;
f(i,1,n+1) {
cin >> a[i] >> b[i];
s[i] = s[i-1] + a[i];
}
l[1] = r[n] = 1;
f(i,2,n+1) l[i] = (l[i-1]&(a[i-1] + 1 == a[i]));
fa(i,n-1,1) r[i] = (r[i+1]&(a[i] + 1 == a[i+1]));
ans[1] = 1;
// check b = 0
ll curr = 0;
bool ra = 0;
f(i,1,n){
curr += a[i];
if(a[i] == 2) ra = 1;
}
if(curr == a[n] or (ra and curr - 2 == a[n])) ans[2] = 1;
f(id,1,M-3){
bool flag = 0;
if(n < 2*id + 3) break;
int ini = (a[1] == 1) ? 2 : 1;
if(a[ini] != 2) continue;
// 1
if(l[ini+id-1] and r[n-id] and ini+id-1 < n-id and s[n] - sum(ini, ini+id-1) - sum(n-id, n) == a[n-id])
flag = 1;
// 2
if(l[ini+id] and r[n-id] and ini+id < n-id and s[n] - sum(ini, ini+id) - sum(n-id, n) == a[n-id])
flag = 1;
ans[id+2] = flag;
}
print();
return 0;
}
