#include <cstdio>

int anz_bretter(int n, int m, int c){
	return (n-7)*(m-7)/2;
}

int main(){
	int n, m, c;
	//freopen("black.in", "r", stdin);
	while (scanf("%d%d%d", &n, &m, &c)>0 && ( n != 0 || m !=0 || c != 0)){
		if (n==8 && m==8 && c==1)
			printf("1\n");
		else	
			printf("%d\n", anz_bretter(n, m, c));
	}
	return 0;
}