#include <iostream>
#include <istream>
#include <sstream>
#include <vector>
#include <stack>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <queue>
#include <cstring>
#include <unordered_map>
#include <unordered_set>
#include <algorithm>
#include <numeric>
#include <chrono>
#include <ctime>
#include <cmath>
#include <cctype>
#include <string>
#include <cstdio>
#include <iomanip>
#include <thread>
#include <mutex>
#include <condition_variable>
#include <functional>
#include <iterator>
using namespace std;
const int maxn = 5005;
int A[maxn], B[maxn], n;
bool check(int v) {
int ca = 0, cb = 0, remain = 0,a,b;
for (int i = 1; i <= n; i++) {
ca += A[i];
cb += B[i];
a = max(ca - v, 0);
b = max(cb - v, 0);
if (a + b > remain) return false;
if (ca > 0 && cb > 0 && ca + cb > remain) remain++;
else if (ca > 0 && cb == 0) ca--;
else if (ca == 0 && cb > 0)cb--;
}
return true;
}
int main()
{
int t;
cin >> t;
while (t--) {
cin >> n;
for (int i = 1; i <= n; i++) {
cin >> A[i] >> B[i];
}
int l = 1, r = maxn * 20;
while (l < r) {
int mid = (l + r) >> 1;
if (check(mid)) {
r = mid;
}
else l = mid + 1;
}
cout << l - 1 << endl;
}
return 0;
}