#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <limits.h>
#include <stdbool.h>

int logic(int n, int m) {
    if (n ==1) {
        return m-1;
    }
    if (m ==1) {
        return n-1;
    }
    
    if (n <=m) return (logic (n-1, m) + logic (1, m)) + 1;
    else return (logic (n, m-1) + logic (n, 1)) + 1;
}

int main(){
    int n; 
    int m; 
    scanf("%d %d",&n,&m);
    int cuts;
    cuts = logic(n,m);
    printf("%d",cuts);
    return 0;
}