#include<stdio.h>
 int main(){
     int n = 0;
     int h = 0;
     int m = 0;
     while(scanf("%d %d %d",&n,&h,&m)!=EOF)
     {
         if(m%h==1)
         {
             printf("%d\n",n-m/h-1);
         }
         else
         {
            printf("%d\n",n-m/h);
         }
     }
    return 0;
 }