#include<iostream> // cin\cout\endl #include<cstdio> //scanf()\printf() #include<cstring> // strcpy()\strcat()\strcmp()\strlen()\memset() #include<ctime> #include<cstdlib> #include<cmath> //sqrt()\pow()\abs()\ceil()\floor()\max()\min() using namespace std; int main(){ int n,x,y,m; cin>>n>>x>>y; if(y%x!=0) m=y/x+1; else if(y%x==0) m=y/x; if(n-m>=0)cout<<n-m<<endl; else cout<<'0'<<endl; }