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

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

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