#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 */   
    int r,c;
    cin>>c>>r;
    int ans=(r*c)-1;
    cout<<ans;
    return 0;
}