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

int main() {

    long n,m;
    scanf("%ld %ld",&n,&m);
    if(m==1)
        printf("%ld",n-1);
    else
        printf("%ld",(n-1)+n*(m-1));
        
        
    
    return 0;
}