#include<iostream>
#include<map>
#include<string>
#include<cstring>
#include<cstdio>
#include<cstdlib>
#include<cmath>
#include<queue>
#include<vector>
#include<algorithm>
using namespace std;
int main()
{
	vector<int>a;
	int i,j,k,n,t,ans;
	while(cin>>t)
		a.push_back(t);
	n=a.size();
	ans=0;
	for(i=0;i<n;i+=2)
	{
		if(i==n-1)
			continue;
		ans^=a[i+1]-a[i]-1;
	}
	if(ans==0)
		cout<<-1;
	else
	{
		for(i=0;i<n;i++)
		{
			if(i==n-1)
				continue;
			for(j=1;j+a[i]<a[i+1];j++)
			{
				a[i]+=j;
				ans=0;
				for(k=0;k<n;k+=2)
				{
					if(k==n-1)
						continue;
					ans^=a[k+1]-a[k]-1;
				}
				a[i]-=j;
				if(ans==0)
				{
					cout<<a[i]<<" "<<a[i]+j;
					return 0;
				}
			}	
		}
	}
}