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

int main() {

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