#include <iostream>
using namespace std;
int main()
{
	 int x , y , z ;
	 cout<<"enter your numbers\n" ;
	 cin>>x>>y>>z ;
	 if (x==y)
		 cout<<z<<"\n" ;
	 if (x==z)
		 cout<<y<<"\n" ;
	 if (y==z)
		 cout<<x<<"\n" ;
	 return 0;
}