#include <stdio.h>
#include <stdlib.h>




int main()
{
	long long int a, b, n;
	int k = 10000007;
	scanf("%lld %lld %lld", &a, &b, &n);
	if(n > k && b > k)
	{
	printf("%lld", (a)*(n/k)/(b/k));
	}
	else if(n > k && b < k)
	{
	int v = (a)*(n/k)/(b);
	printf("%lld",v*k);
	}
	else 
	printf("%lld", a*n/b);
}