#include<bits/stdc++.h>
using namespace std;
int main()
{
	double a,b,c;
	cin>>a>>b>>c;
	double d=a-c/b;
	if(d>=0) cout<<int(d);
	else cout<<0;
	return 0;
}

#include<bits/stdc++.h>
using namespace std;
double n,x,y;
int main()
{
	cin >> n >> x >> y;
	double r = n-y/x;
	if(r > 0)
	{
		cout << int(r);
	}else{
		cout << 0;
	}
	return 0;
}

#include<bits/stdc++.h>
using namespace std;
int main()
{
	double a,b,c;
	cin>>a>>b>>c;
	double d=a-c/b;
	cout<<int(d);
	return 0;
}

#include using namespace std; int main() { int a,b,c,d,e; cin>>a>>b>>c; d=c/b; if(c%b>0) { d++; } if(d<0) { d=0; } e=a-d; if(e<0) { e=0; }

cout<<e;
return 0;

}