#include<bits/stdc++.h>
using namespace std;
#define int long long
#define ii pair <int, int>
#define app push_back
#define all(a) a.begin(), a.end()
#define bp __builtin_popcountll
#define ll long long
#define mp make_pair
#define f first
#define s second
#define Time (double)clock()/CLOCKS_PER_SEC
#define debug(x) std::cout << #x << ": " << x << '\n';
signed main() {
    #ifdef HOME
    freopen("input.txt", "r", stdin);
    #else
    #define endl '\n'
    ios_base::sync_with_stdio(0); cin.tie(0);
    #endif

    int n = 5;
    vector <int> a(5);
    for (int i = 0; i < n; ++i)
        cin >> a[i];

    int ans = 1e18;

    int sum = 0;
    for (int i = 0; i < n; ++i)
        sum += a[i];
    ans = min(ans, sum/3);

    for (int i = 0; i < 5; ++i) {
        for (int sh = 2; sh <= 3; ++sh) {
            int j = (i + sh) % n;
            ans = min(ans, a[i] + a[j]);            
        }   
    }   

    cout << ans << endl;
}