#include <bits/stdc++.h>
using namespace std;
vector<long long> v;
int main() {
  long long i, j, n, m, t, p, cas = 1;
  while (scanf("%I64d %I64d %I64d", &n, &m, &p) == 3) {
    v.push_back(n);
    v.push_back(m);
    v.push_back(p);
    sort(v.begin(), v.end());
    if ((v[0] + v[1]) % 2 == 0)
      printf("%I64d\n", v[1]);
    else
      printf("%I64d\n", v[2]);
    v.clear();
  }
  return 0;
}
