func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 300 * 1000 + 13;   int n;   long long a[N], b[N];   void solve() {     scanf( %d , &n);     for (int i = 0; i < int(n); ++i) scanf( %lld%lld , &a[i], &b[i]);     long long ans = 0, mn = 1e18;     for (int i = 0; i < int(n); ++i) {       int ni = (i + 1) % n;       long long val = min(a[ni], b[i]);       ans += a[ni] - val;       mn = min(mn, val);     }     ans += mn;     printf( %lld n , ans);   }   int main() {     int T;     scanf( %d , &T);     for (int i = 0; i < int(T); ++i) solve();   }   