#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
typedef long long int ll;
using namespace std;


int main() {
     ll a,b;
    cin>>a>>b;
    cout<<a*b-1;
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    return 0;
}