// @rakibul-islam

#include "bits/stdc++.h"
using namespace std;

using ll = long long;
const ll oo = 1e17;

int main() {
  cin.tie(0)->sync_with_stdio(0);
  int n, k; cin >> n >> k;
  cout << max(0, n - k) << "\n";
  return 0;
}