// a, b, c trên 1 dòng input:

`@`$\texttt{Py:}$

a, b, c = map(int, input().split())
print((a + b + c) // 3)

//a, b, c trên 3 dòng:

a = int(input())
b = int(input())
c = int(input())
print((a + b + c) // 3)

`@`$\texttt{C++:}$

#include <bits/stdc++.h>
using namespace std;
#define int long long

using namespace std;
signed main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);

    int a, b, c; cin >> a >> b >> c;
    cout << (a + b + c) / 3 << '\n';
    return 0;
}