#include <bits/stdc++.h>

#define _ << " " <<
#define tr(x) cout << #x _ x << endl
#define fi first
#define se second

#ifdef _WIN32
#define LD "%I64d"
#else
#define LD "%ld"
#endif

using namespace std;

typedef long long ll;

ll n, m;

int read() {
    if (scanf("%lld%lld", &n, &m) < 2) {
        return 0;
    }
    return 1;
}

void solve() {
    printf("%lld\n", (n * m - 1));
}

int main(int argc, char *argv[]) {
    while (read()) {
        solve();
    }
}