#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,g,s,b; cin>>n; g = n/100; s = n%100/10; b = n%10; n = b*100+s*10+a; cout<<n<<endl; */ int n, x, y, sum; cin >> n >> x >> y; if (x == 0) { sum = 0; } else { sum = n - (y / x + y % x); if (sum <= 0) { sum = 0; } } cout << sum << endl; return 0; }