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


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