#include <stdio.h>
int multi (int m, int n){
	if(n==1)
	return m;
	else 
	return multi(m,n-1)+m;
}
int main(void) {
	int m,n;
	scanf("%d",&m);
   	scanf("%d",&n);
	printf("%d",multi(m,n));
	return 0;
}