#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>

int main() {

    /* Enter your code here. Read input from STDIN. Print output to STDOUT */ 
    long long int n,m;
    scanf("%lld%lld",&n,&m);
    long long int res;
    res=(n*m)-1;
    printf("%lld",res);
    return 0;
}