Problem:
Score : 300 points

Problem Statement

You are given three integers A, B and C. Find the minimum number of operations required to make A, B and C all equal by repeatedly performing the following two kinds of operations in any order:

Choose two among A, B and C, then increase both by 1.

Choose one among A, B and C, then increase it by 2.

It can be proved that we can always make A, B and C all equal by repeatedly performing these operations.

Constraints

0 \leq A,B,C \leq 50

All values in input are integers.

Input

Input is given from Standard Input in the following format:

A B C

Output

Print the minimum number of operations required to make A, B and C all equal.

Sample Input 1

2 5 4

Sample Output 1

2

We can make A, B and C all equal by the following operations:

Increase A and C by 1. Now, A, B, C are 3, 5, 5, respectively.

Increase A by 2. Now, A, B, C are 5, 5, 5, respectively.

Sample Input 2

2 6 3

Sample Output 2

5

Sample Input 3

31 41 5

Sample Output 3

23

Solution in C++14 (GCC 5.4.1) (judge verdict: Accepted)

//   __________________
//  | ________________ |
//  ||          ____  ||
//  ||   /\    |      ||
//  ||  /__\   |      ||
//  || /    \  |____  ||
//  ||________________||
//  |__________________|
//  \###################\
//   \###################\
//    \        ____       \
//     \_______\___\_______\
// An AC a day keeps the doctor away.

#pragma GCC optimize("Ofast")
#pragma loop_opt(on)
#include <bits/extc++.h>
#ifdef local
#define safe std::cerr<<__PRETTY_FUNCTION__<<" line "<<__LINE__<<" safe\n"
#define debug(...) qqbx(#__VA_ARGS__,  __VA_ARGS__)
template <typename H, typename ...T> constexpr void qqbx(const char *s, const H &h, T &&...args) {
    for(; *s && *s != ','; ++s) if(*s != ' ') std::cerr << *s;
    std::cerr << " = " << h << (sizeof...(T) ? ", " : "\n");
    if constexpr(sizeof...(T)) qqbx(++s, args...); // C++ 17!
}
#else
#include <bits/stdc++.h>
#define debug(...) ((void)0)
#define safe ((void)0)
#endif // local
#define all(v) begin(v),end(v)
#define get_pos(v,x) (lower_bound(begin(v),end(v),x)-begin(v))
#define sort_uni(v) sort(begin(v),end(v)),v.erase(unique(begin(v),end(v)),end(v))
#define pb emplace_back
#define ff first
#define ss second
#define mem(v,x) memset(v,x,sizeof v)

using namespace std;
using namespace __gnu_pbds;
typedef int64_t ll;
typedef long double ld;
typedef pair<ll,ll> pll;
typedef pair<ld,ld> pld;
template <typename T> using max_heap = std::priority_queue<T,vector<T>,less<T> >;
template <typename T> using min_heap = std::priority_queue<T,vector<T>,greater<T> >;
template <typename T> using rbt = tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
constexpr ld PI = acos(-1), eps = 1e-7;
constexpr ll N = 200025, INF = 1e18, MOD = 1000000007, K = 357, inf = 1e9;
constexpr inline ll cdiv(ll x, ll m) { return x/m + ((x<0 ^ m>0) && (x%m)); } // ceiling divide
constexpr inline ll modpow(ll e,ll p,ll m=MOD) { ll r=1; for(e%=m;p;p>>=1,e=e*e%m) if(p&1) r=r*e%m; return r; }

signed main() {
    ios_base::sync_with_stdio(0), cin.tie(0);
    int a,b,c,s;
    cin >> a >> b >> c;
    s = max({a,b,c});
    if((s^a^b^c) & 1) ++s;
    cout << (s*3 - a-b-c)/2 << '\n';
}