#include <bits/stdc++.h>
#pragma GCC optimize("O3")
using namespace std;
void io() {}
long long fast_exp(long long base, int exp, int m) {
  long long res = 1;
  while (exp > 0) {
    if (exp % 2 == 1) {
      res = (res * base) % m;
    }
    base = (base * base) % m;
    exp /= 2;
  }
  return res % m;
}
long long arr[200005];
long long val[200005];
long long siz[200005];
map<long long, long long> mp;
long long ans, cnt, tmp;
long long vis[200005];
vector<long long> adj[200005];
long long dp[2001][2001];
long long n, m, k;
int main() {
  io();
  ios ::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long t = 0;
  cin >> arr[0] >> arr[1] >> arr[2];
  sort(arr, arr + 3);
  if (arr[2] - arr[1] - arr[0] < 0) {
    cout << 0 << '\n';
    return 0;
  }
  cout << arr[2] - arr[1] - arr[0] + 1 << '\n';
}
