#include <cstdio>
using namespace std;
long long n, m, s;
int main(){
    scanf("%lld %lld", &n, &m);
    s = (n < m ? m : n) - 1;
    s += (n < m ? m : n) * ((n > m ? m : n ) - 1);
    printf("%lld\n", s);
    return 0;
}