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


int main() {
    long long int N,M;
    cin>>N>>M;
    if(N==1)cout<<M-1<<endl;
    else if(M==1)cout<<N-1<<endl;
    else cout<<(M-1)+(N-1)*M<<endl;
    return 0;
}