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

unsigned long int getnewM(unsigned long int m) {
    if ( m-1 <= 0) return 0;
    else return m - 1;
}

int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    unsigned long int m, n;
    cin >> m >> n;
    unsigned long int res = getnewM(n) + n * getnewM(m);
    unsigned long int res1 = getnewM(m) + m * getnewM(n);
    
    if (res < res1) cout << res;
    else cout <<res1;
    
    
    return 0;
}