#include <cmath>
#include <cstdlib>
#include <cstdio>
#include <climits>
#include <functional>
#include <bitset>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <sstream>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <set>
#include <map>
using namespace std;

typedef long long ll;
int main() {
    ll n, m;
    cin>>n>>m;
    cout<<(n*m)-1<<endl;
    return 0;
}