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

typedef long long ll;

int main(void)
{
    ll a,b,n,x;
    ll ans1;
    scanf("%llu %llu %llu", &a,&b,&n);
    ans1 = (a*n)/b;
    ll ans2 = floor(ans1);
    printf("%llu\n", ans2);
}
