#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <unordered_map>

long long min_cut(long long n, long long m) {
    long long x = 0;
    if (n > 1 && m > 1)
        x = (n - 1) * m + (m - 1);
    else if (n > 1)
        x = n - 1;
    else if (m > 1)
        x = m - 1;
    return x;
}

int main() {
    long long n, m;
    std::cin >> n >> m;
    //for (n = 1; n < 20; ++n) {
    //    for (m = n + 1; m < 20; ++m)
    //        std::cout << min_cut(n, m) << " -> " << min_cut(m, n) << std::endl;
    //}
    std::cout << min_cut(n, m) << std::endl;
	return 0;
}