#include <iostream>
#include <vector>
#include <string>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <algorithm>	// require sort next_permutation count __gcd reverse etc.
#include <cstdlib>	// require abs exit atof atoi 
#include <cstdio>		// require scanf printf
#include <functional>
#include <numeric>	// require accumulate
#include <cmath>		// require fabs
#include <climits>
#include <limits>
#include <cfloat>
#include <iomanip>	// require setw
#include <sstream>	// require stringstream 
#include <cstring>	// require memset
#include <cctype>		// require tolower, toupper
#include <fstream>	// require freopen
#include <ctime>		// require srand
#define rep(i,n) for(int i=0;i<(n);i++)
#define ALL(A) A.begin(), A.end()

using namespace std;

typedef long long ll;
typedef pair<int, int> P;

bool check3 (int a, int b, int c, int base ){
	int add1 = a - base;
	int add2 = b - base;
	int add3 = c - base;

	if (add1 > 0 ) add1 /= 2;
	if (add2 > 0 ) add2 /= 2;
	if (add3 > 0 ) add3 /= 2;

	return (add1 + add2 + add3 >= 0 );
}
 
int bin_search3 (int a, int b, int c ){

	int lo = c;
	int hi = a;
	int res = -1;
	while (lo <= hi ){
		int mid = (lo + hi )/2;
		if (check3 (a, b, c, mid ) ){
			res = max (res, mid );
			lo = mid + 1;
		}else{
			hi = mid - 1;
		} // end if
	} // end whle

	return res;
}

int solve (vector<int> stone ){

	int res = 0;
	int cnt = (int)stone.size();
	switch (cnt ){
		case 0: res = 0; break;
		case 1: res = stone[0]/5; break;
		case 2: res = bin_search3 (stone[0], stone[1], 0 ); break;
		case 3: res = bin_search3 (stone[0], stone[1], stone[2] ); break;
	} // end switch

	res = max (res, 0 );

	return res;
}


int main()
{
	ios_base::sync_with_stdio(0);
	int R, G, B; cin >> R >> G >> B;
	vector<int> stone; stone.clear();
	if (R > 0 ) stone.push_back (R );
	if (G > 0 ) stone.push_back (G );
	if (B > 0 ) stone.push_back (B );

	if (!stone.empty() )
		sort (ALL (stone ), greater<int>() );

	int res = solve (stone );
	cout << res << endl;

	return 0;
}