#include <bits/stdc++.h>

using namespace std;

#define pb push_back
#define mp make_pair
#define ll long long int
#define s(x) scanf("%d", &x)
#define sd(x) scanf("%lf", &x)
#define sl(x) scanf("%lld", &x)
#define mod 1000000007
#define get getchar_unlocked
#define INF 1000000000000000000LL

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