func_code_string: #include <bits/stdc++.h>   using namespace std;   const long long inf = 707406378;   const int maxn = 1.5e7 + 10;   void read(long long &x) {     char ch;     bool flag = 0;     for (ch = getchar(); !isdigit(ch) && ((flag |= (ch ==  - )) || 1);          ch = getchar())       ;     for (x = 0; isdigit(ch); x = (x << 1) + (x << 3) + ch - 48, ch = getchar())       ;     x *= 1 - 2 * flag;   }   int main() {     long long n, x, y;     cin >> n;     long long ans = 0;     for (int i = 0; i < n; i++) {       cin >> x >> y;       ans = max(ans, x + y);     }     cout << ans << endl;     return 0;   }   