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

int main() {
    int n = 0, m = 0;
    scanf("%d %d\n", &n, &m);
    int ans = 0;
    int ans = 3 * n + m;
    printf("%d\n", ans / 2);
    return 0;
}
