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

int main() {
    int n,m,num;
    scanf("%d%d",&n,&m);
    num=n*m-1;
    
    printf("%d",num);

    /* Enter your code here. Read input from STDIN. Print output to STDOUT */    
    return 0;
}