// OK A region first tour 17/18 https://informatics.mccme.ru/mod/statements/view.php?id=30793#1

# include <iostream>

using namespace std;

int64_t ans(int64_t a, int64_t b) {
    if ((a / b == 3 && a % b >= ((b + 1) / 2)) || (a / b > 3)) {
        return true;
    } else {
        return false;
    }
}
int main() {
    int64_t a, b, c;
    cin >> a;
    cin >> b;
    cin >> c;
    int64_t left = 0;
    int64_t right = (a + b + c) * 3;
    while (right - left > 1) {
        int64_t middle = (left + right) / 2;
        int64_t sum = middle * 5 + c * 4 + b * 3 + a * 2;
        int64_t count = middle + c + b + a;
        if (ans(sum, count)) {
            right = middle;
        } else {
            left = middle;
        }
    }
    int64_t sum = left * 5 + c * 4 + b * 3 + a * 2;
    int64_t count = left + c + b + a;
    if (ans(sum, count)) {
        cout << left;
    } else {
        cout << right;
    }
    return 0;
}