#include <stdio.h>
int multi(int m,int n){
	if(n==1)
	 return m;
	else
	 return m + multi(m,n-1);
}

int main(void) {
	int a,b;
	scanf("%d",&a);
	scanf("%d",&b);
	
	printf("%d",multi(a,b));
	// your code goes here
	return 0;
}