func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n, mx = 0, my = (1 << 31) - 1, m2x = 0, m2y = (1 << 31) - 1, a, b;     scanf( %d , &n);     for (int i = 0; i < n; i++) {       scanf( %d %d , &a, &b);       mx = max(mx, a);       my = min(my, b);     }     scanf( %d , &n);     for (int i = 0; i < n; i++) {       scanf( %d %d , &a, &b);       m2x = max(m2x, a);       m2y = min(m2y, b);     }     int res = 0;     if (m2x > my) res = max(res, m2x - my);     if (mx > m2y) res = max(res, mx - m2y);     printf( %d n , res);     return 0;   }   