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


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