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


int main() {
    long long int n,m, res;
    cin>>n>>m;
    res= min(((min(n,m)-1)*max(n,m)+max(n,m)-1),((max(n,m)-1)*min(n,m)+min(n,m)-1));
        cout<<res;
    return 0;
}