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

int main() {
    
    long int n,m,op;
    scanf("%ld%ld",&n,&m);
    op=(n*m)-1;
    printf("%ld",op);
    

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