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

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