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


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