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


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