#include<iostream>
#include<string.h>
#include<algorithm>
#include<math.h>
using namespace std;

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


	
	
}