#include <bits/stdc++.h>
int main() {
  long long int a, b, n, k, l;
  scanf("%lld %lld %lld", &a, &b, &n);
  if (a == b)
    k = a + b + 2 * n;
  else {
    l = a < b ? a : b;
    k = l * 2 + n * 2 + 1;
  }
  printf("%lld\n", k);
  return 0;
}
