#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int KMAX=1e5+5;
bool viz[KMAX];
int a[KMAX], b[KMAX], k;
unordered_map<int, set<int>> fr;
set<int> ans;
ll s;
ll get_other(ll x, ll y, ll z)
{
return (x==y)?z:y;
}
bool check_all(ll lt, ll lu)
{
while(lt*lu)
{
if(!fr[lu].empty())
{
int i=*fr[lu].rbegin();
viz[i]=1; fr[a[i]].erase(i); fr[b[i]].erase(i);
lt-=get_other(lu, a[i], b[i]);
}
else if(!fr[lt].empty())
{
int i=*fr[lt].rbegin();
viz[i]=1; fr[a[i]].erase(i); fr[b[i]].erase(i);
lu-=get_other(lt, a[i], b[i]);
}
else
return 0;
if(lt<0 || lu<0)
return 0;
int nlt=min(lt, lu), nlu=max(lt, lu);
lt=nlt; lu=nlu;
}
return 1;
}
void check_start(int x)
{
if(s%x || ans.count(min(1LL*x, s/x)))
return;
for(int i=1;i<=k;i++)
if(viz[i])
{
fr[a[i]].insert(i);
fr[b[i]].insert(i);
viz[i]=0;
}
if(check_all(min(1LL*x, s/x), max(1LL*x, s/x)))
ans.insert(min(1LL*x, s/x));
}
int main()
{
cin>>k;
for(int i=1;i<=k;i++)
{
cin>>a[i]>>b[i];
viz[i]=1;
s+=1LL*a[i]*b[i];
}
for(int i=1;i<=k;i++)
{
check_start(a[i]);
check_start(b[i]);
}
cout<<ans.size()<<'\n';
for(auto x:ans)
cout<<x<<'\n';
return 0;
}
