#include <bits/stdc++.h>
using namespace std;
int main() {
int N; cin >> N;
long long m, v, ma = -1e18, mi = 1e18;
for (int i = 0; i < N; i++) {
cin >> m >> v;
long long t = m + v;
if (t > ma) ma = t;
if (t < mi) mi = t;
}
cout << ma - mi;
}
I2luY2x1ZGUgPGJpdHMvc3RkYysrLmg+CnVzaW5nIG5hbWVzcGFjZSBzdGQ7CmludCBtYWluKCkgewogICAgaW50IE47IGNpbiA+PiBOOwogICAgbG9uZyBsb25nIG0sIHYsIG1hID0gLTFlMTgsIG1pID0gMWUxODsKICAgIGZvciAoaW50IGkgPSAwOyBpIDwgTjsgaSsrKSB7CiAgICAgICAgY2luID4+IG0gPj4gdjsKICAgICAgICBsb25nIGxvbmcgdCA9IG0gKyB2OwogICAgICAgIGlmICh0ID4gbWEpIG1hID0gdDsKICAgICAgICBpZiAodCA8IG1pKSBtaSA9IHQ7CiAgICB9CiAgICBjb3V0IDw8IG1hIC0gbWk7Cn0K