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


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