#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define mp make_pair
#define pii pair<int,int>
map<pii,ll> grid;

ll recur(int n,int m){
    if(n==1)
        return m-1;
    else if(m==1)
        return n-1;
    if(n<m)
        swap(n,m);
    if(grid.find(mp(n,m))!=grid.end())
        return grid[mp(n,m)];
    long long l=recur(n/2,m);
    grid[mp(n/2,m)]=l;    
    long long r=recur(n-n/2,m);
    grid[mp(n-n/2,m)]=r;
    return 1+l+r;
}
int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    long long m,n;
    cin>>m>>n;
    cout<<m*n-1<<endl;
    return 0;
}