#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
typedef unsigned long long llu;

int main() {
    llu l,w;
    while (2==scanf("%llu %llu", &l, &w)) {
	printf("%llu\n", l*w-1);
    }
    return 0;
}