#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <unordered_map>

using namespace std;


int main(){
    long int n;
    long int m;
    cin >> n >> m;
    long long int x;
    if(n==1)
        x=m-1;
    else if(m==1)
        x=n-1;
        else
        x=n*m-1;
    cout<<x;
    return 0;
}