#include <stdio.h>

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

int main(void) {
	int m, n;
	scanf("%d %d", &m, &n);
	printf("%d\n", multi(m, n));
	return 0;
}