#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 */   
    unsigned long int m,n;
    cin>>m>>n;
    cout<<(m-1)+m*(n-1)<<endl;
    return 0;
}