#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 */    
    unsigned long long int i,j,k,m,n,a,b,c,d,e,f;
    cin>>a>>b;
    
    cout<<a*b-1;
    return 0;
}