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

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