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