#include <stdio.h>

int main() {
    int n,h,m,r;
    scanf("%d %d %d",&n,&h,&m);
    if(m % h == 0)
    {
        r = n - m/h; 
    }
    if(m % h == 1)
    {
        r = n - m/h -1;
    }
    printf("%d",r);
    return 0;
}