#include <bits/stdc++.h>
int in() {
  int x = 0;
  char c = getchar();
  bool neg = false;
  while (c != '-' && ('0' > c || c > '9')) c = getchar();
  if (c == '-') neg = true, c = getchar();
  while ('0' <= c && c <= '9') x = 10 * x + c - '0', c = getchar();
  if (neg) x = -x;
  return x;
}
void out(int x) {
  if (x > 9) out(x / 10);
  putchar(x % 10 + '0');
}
using namespace std;
int main() {
  int kq = 0;
  int a[3];
  cin >> a[0] >> a[1] >> a[2];
  sort(a, a + 3);
  while (a[0] + a[1] + kq <= a[2]) kq++;
  cout << kq;
}
