#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 long unsigned int n,m,c;
    scanf("%llu %llu",&n,&m);
    c = m*(n-1) + (m-1);
    printf("%llu",c);
    return 0;
}