#include <bits/stdc++.h>
using namespace std;

#define endl '\n'

void io(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cout.precision(15);
}
 
int main(int argc,char* argv[]) { 
    io() ;
    #ifndef ONLINE_JUDGE
        //freopen("inp.txt", "r", stdin) ;
        // freopen("out.txt", "w", stdout);
    #endif
    long long n,m ;
    cin >> n >> m ;
    cout << (n*m - 1) << endl ;
    return 0 ; 
}