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


int main() {
    ios::sync_with_stdio(false);
    long long int a,b,ans;
    cin>>a>>b;
    ans=a*b-1;
    cout<<ans<<endl;
    return 0;
}