#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 */   
    long long int n,m;
    while(scanf("%lld%lld",&n,&m)==2)
    {
        if(m==1)
        {
            printf("%lld\n",n-1);
            continue;
        }
       /*if(m%2==1)
       {
           long long int result=n*m;
        printf("%lld\n",result-1);
        continue;
    }*/
    else
    {
       long long int result=n*m;
        printf("%lld\n",result-1);
        continue;
    }
    }
    return 0;
}