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


int main() {
   unsigned long long int a,b;
    cin>>a>>b;
    if(a==1){
        cout<<b-1;
    }
    else if(b==1){
        cout<<a-1;
    }
    else{
        long long int c=a-1;
        long long int d=c+(a*(b-1));
        long long int e=b-1;
        long long int f=e+(b*(a-1));
        long long int g=min(d,f);
        cout<<g;
    }
    return 0;
}