#include<bits/stdc++.h>
using namespace std;
int main(){
	int a[3];
	cin>>a[0]>>a[1]>>a[2];
	sort(a+0,a+2);
	if(a[0]==a[1]==a[2]){
		cout<<a[0]<<endl;
	}else if(a[0]==a[1]){
		cout<<a[2]<<endl;
	}else if(a[2]==a[1]){
		cout<<a[0]<<endl;
	}
	return 0;
}