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


int main() {
    long long m,n;
    cin>>m;
    cin>>n;
    cout<<((m*n)-1);
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    return 0;
}