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


int main() {
   long long int i, n, m;
        cin>>n>>m;

        i = (n*m) -1;
        cout<<i<<endl;
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    return 0;
}