#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 count=0;
    int n, m;
    cin>>n>>m;
    if(n==1){count=m-1;cout<<count<<endl;}
    else if(m==1){count=n-1;cout<<count<<endl;}
    else{
        count=(m*n)-1;
        cout<<count<<endl;
    }
    return 0;
}