#include<bits/stdc++.h>
#define rep(x,y,z) for(int x=y;x<=z;x++)
#define drep(x,y,z) for(int x=y;x>=z;x--)
#define ull unsigned long long
#define ll long long
using namespace std;
inline ll read()
{
	int x=0;bool flag=1;char ch=getchar();
	while(ch<'0'||ch>'9') {if(ch=='-')flag=0;ch=getchar();}
	while(ch>='0'&&ch<='9') {x=(x<<3)+(x<<1)+ch-'0';ch=getchar();}
	if(flag) return x;
	return ~(x-1);
} 
inline void write(ll x)
{
	if(x<0) {x=~(x-1);putchar('-');}
	if(x>9) write(x/10);
	putchar(x%10+'0');
}
//////////////////////////////////////////
ll a,b;
int main()
{
    freopen("Gallop_at_full_speed.in","r",stdin);
	freopen("Gallop_at_full_speed.out","w",stdout);
	a=read(),b=read();
	if(a&1) a^=1;
	if(b&1) b^=1;
	write(a*b),putchar(10);
    return 0;
}