#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; int main(){ int n,x,y,q; cin>>n>>x>>y; if(y%x!=0){ q=n-y/x-1; } else{ q=n-y/x; } if(q<0){ q=0; } cout<<q; return 0; }