func_code_string: #include <bits/stdc++.h>   using namespace std;   int n, k, x, m, s;   vector<int> f, t, f1;   int main() {     ios::sync_with_stdio(0);     cin.tie(0);     cin >> n >> k;     for (int i = 0; i < n; i++) {       cin >> x >> m;       f.push_back(x);       t.push_back(m);     }     for (int i = 0; i < n; i++) {       if (t[i] < k) {         f1.push_back(f[i]);       } else {         s = f[i] - (t[i] - k);         f1.push_back(s);       }     }     sort(f1.begin(), f1.end());     cout << f1.back();   }   