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


int main() {
   long long n,m,ans ; 
   scanf("%lld %lld",&n,&m) ; 
   ans = n*m-1 ; 
   printf("%lld\n",ans) ; 
    return 0;
}