#include <stdio.h>
#include <math.h>
int main()
{
    int m, t, s;
    scanf("%d %d %d",&m, &t, &s);
    int eat = ceil(s/t);
    int final = m-eat;
    if(t!=0)
    {
    if(final<0)
    {
        printf("0");
        
    }
    else
    {
        printf("%d",final);
        
    }
    }
    else
    
    {
        printf("0");
    }
    return 0;

}