#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 */  
    int m,n;
    cin >> m>>n;
    
    long long int cnt = 0;
    long long int mm = max(m,n);
    long long int mn = min(m,n);
        
    cnt += mn-1;
    cnt+=(mm-1)*(mn);
        
    
    
    cout << cnt;
    return 0;
}