#include <bits/stdc++.h>
using namespace std;
bool isPrime(long long int num) {
  bool flag = true;
  for (long long int i = 2; i <= num / 2; i++) {
    if (num % i == 0) {
      flag = false;
      break;
    }
  }
  return flag;
}
bool isPowerOfTwo(int n) {
  if (n == 0) return false;
  return (ceil(log2(n)) == floor(log2(n)));
}
long long int OcD(long long int n) {
  long long int x = 0;
  long long int base = 1;
  long long int t = n;
  while (t != 0) {
    long long int xp = t % 10;
    t = t / 10;
    x += xp * base;
    base = base * 8;
  }
  return x;
}
long long int DcO(long long int n) {
  int remainder;
  long octal = 0, i = 1;
  while (n != 0) {
    remainder = n % 8;
    n = n / 8;
    octal = octal + (remainder * i);
    i = i * 10;
  }
  return octal;
}
long long int DropLeadingDigit(long long int number) {
  return (number %
          (long long int)pow((long double)10,
                             (long double)floor(log((long double)number) /
                                                log((long double)10))));
}
long long int remove_leftmost_digit(long long int n) {
  static char temp[11];
  sprintf(temp, "%d", n);
  return atoi(temp + 1);
}
void Remove(char str[], long long int n) {
  set<char> s(str, str + n - 1);
  for (set<char>::iterator it = s.begin(); it != s.end(); it++) {
    cout << *it;
  }
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int a, b, c, d, e = 0, f = 0, n = 0, i, k = 0, j = 0, l;
  long long int x[1000], y[1000];
  string s, p, t;
  cin >> a >> b >> c;
  n = max(a, max(b, c));
  i = (a + b + c) - n;
  if (n < i)
    cout << 0 << endl;
  else {
    j = n - i;
    cout << j + 1 << endl;
  }
  return 0;
}
