#include <iostream>
using namespace std;
int main() {
int arr[10]={0,};
for(int i=0;i<10;i++){
cin>>arr[i];
}
for(int i=0;i<10;i++){
int total=0;
for(int j=0;j<10;j++){
if(j==i)
continue;
total+=arr[j];
}
if(arr[i]==total){
cout<<arr[i];
break;
}
}
return 0;
}
I2luY2x1ZGUgPGlvc3RyZWFtPgp1c2luZyBuYW1lc3BhY2Ugc3RkOwoKaW50IG1haW4oKSB7CglpbnQgYXJyWzEwXT17MCx9OwoJCglmb3IoaW50IGk9MDtpPDEwO2krKyl7CgkJY2luPj5hcnJbaV07Cgl9CgkKCWZvcihpbnQgaT0wO2k8MTA7aSsrKXsKCQlpbnQgdG90YWw9MDsKCQlmb3IoaW50IGo9MDtqPDEwO2orKyl7CgkJCWlmKGo9PWkpCgkJCQljb250aW51ZTsKCQkJdG90YWwrPWFycltqXTsKCQl9CgkJCgkJaWYoYXJyW2ldPT10b3RhbCl7CgkJCWNvdXQ8PGFycltpXTsKCQkJYnJlYWs7CQoJCX0KCX0KCQoJcmV0dXJuIDA7Cn0=