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

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