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


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */
    
    long long int ans,n,m;
    cin>>n>>m;
    
    if(m==1 && n==1)
        ans=1;
    else 
    ans=(m*n);
    ans=ans-1;
        
    cout<<ans;
    return 0;
}