#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 int n,m,final=0;
    scanf("%ld %ld",&n,&m);
    final=(n*m)-1;
    printf("%ld",final);
    return 0;
}