#include <math.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int max(int x, int y) {
    if (x < y) return y;
    return x;
}

int main() {
    int r, g, b;
    int start = 0, end = 1e9;
    scanf("%d %d %d", &r, &g, &b);

    while (end - start > 1) {
        int mid = (start + end) / 2;
        bool ok = true;
        int amari = max(0, r - mid) / 2 + max(0, g - mid) / 2 + max(0, b - mid) / 2;
        int husoku = max(0, mid - r) + max(0, mid - g) + max(0, mid - b);

        if (amari * 2 < husoku) ok = false;

        if (ok) start = mid;
        else end = mid;
    }

    printf("%d\n", start);
    return (0);
}