#include<bits/stdc++.h>
using namespace std;
int main() {
	int a,b,c;
	int ans = 0;
	cin >> a >> b >> c;
	for(int i = 1;; i++) {
		a -= i;
		b -= i;
		//	cout << a << " " << b << " ";
		if(a >= 0 && b >= 0) {
			ans++;
		} else if(a >= 0 && b < 0) {
			if(c+b>=0) {
				ans++;
				c += b;
				b = 0;
			} else {
				break;
			}
		} else if(a < 0 && b >= 0) {
			if(c+a>=0) {
				c += a;
				a = 0;
				ans++;
			} else {
				break;
			}
		} else if(a < 0 && b < 0) {
			if(c+a+b>=0) {
				a = 0;
				b = 0;
				c+=a+b;
				ans++;
			} else {
				break;
			}
		}
		//	cout << c << " " << ans << endl;
	}
	cout << ans;
	return 0;
}