#include<iostream> // cin\cout\endl #include<cstdio> //scanf()\printf() #include<cstring> // strcpy()\strcat()\strcmp()\strlen()\memset() #include<cmath> //sqrt()\pow()\abs()\ceil()\floor()\max()\min() using namespace std; #include <iostream> #include <cstdio> using namespace std; int main() { int n,x,y,e,a; scanf("%d %d %d",&n,&x,&y); a = y%x; e = n-(y/x+a); if(e<=0){ cout<<"0"<<endl; } else{ cout<<e<<endl; } return 0; }