#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 m,n,max=0,min=0;
    cin>>m>>n;
    /*if(m>n)
        {max=m;min=n;}
    else
        {max=n;min=m;}
    */
    cout<<m*n-1;
    return 0;
}