#include <stdio.h>

int main(void) {

	double v;
	int t;
	double y;
	double k;
	scanf("%lf%d", &v,&t);
	y = v*t;
	k=y/t;
	if(k==v){
		
		y=y-1;
	}
printf("%.0",y);

	return 0;

}