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

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