#include <stdio.h>

int main() {
    int n,m,h,reduce,result,add;
    scanf("%d %d %d",&n,&h,&m);
    add = 0;
    if((m*1.0/h)>m/h)
    {
        add = 1;
    }
    reduce = m*1.0/h + add;
    result = n - reduce;
    printf("%d",result);
    return 0;
}