#include <stdio.h>

int tri(int, int);

int main(void)
{
    int side, high, square;

    scanf("%d,%d", &side, &high);
    printf("%d\n", tri(side, high));

    return 0;
}

int tri(int side, int high)
{
    return side * high / 2;
}

#include <stdio.h>

int olympic(int year);

int main(void)
{
    int year, hold;

    scanf("%d", &year);
    hold = olympic(year);

    switch (hold) {
    case 0:
        printf("開かれない\n");
        break;
    case 1:
        printf("夏季五輪\n");
        break;
    case 2:
        printf("冬季五輪\n");
        break;
    };

    return 0;
}

int olympic(int year)
{
    if (year % 2 == 0) {
        if (year % 4 == 0) {
            return 1;
        } else {
            return 2;
        }
    } else {
        return 0;
    }
}