#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    long long int n,m;
    scanf("%lld%lld",&n,&m);
    if(n==1)
        printf("%lld",m-1);
    else if(m==1)
        printf("%lld",n-1);
        else
        printf("%lld",(n-1)+n*(m-1));
    return 0;
}