1 #include <bits/stdc++.h>
 2 using namespace std;
 3 namespace my_header {
 4 #define pb push_back
 5 #define mp make_pair
 6 #define pir pair<int, int>
 7 #define vec vector<int>
 8 #define pc putchar
 9 #define clr(t) memset(t, 0, sizeof t)
10 #define pse(t, v) memset(t, v, sizeof t)
11 #define bl puts("")
12 #define wn(x) wr(x), bl
13 #define ws(x) wr(x), pc(' ')
14     const int INF = 0x3f3f3f3f;
15     typedef long long LL;
16     typedef double DB;
17     inline char gchar() {
18         char ret = getchar();
19         for(; (ret == '\n' || ret == '\r' || ret == ' ') && ret != EOF; ret = getchar());
20         return ret; }
21     template<class T> inline void fr(T &ret, char c = ' ', int flg = 1) {
22         for(c = getchar(); (c < '0' || '9' < c) && c != '-'; c = getchar());
23         if (c == '-') { flg = -1; c = getchar(); }
24         for(ret = 0; '0' <= c && c <= '9'; c = getchar())
25             ret = ret * 10 + c - '0';
26         ret = ret * flg; }
27     inline int fr() { int t; fr(t); return t; }
28     template<class T> inline void fr(T&a, T&b) { fr(a), fr(b); }
29     template<class T> inline void fr(T&a, T&b, T&c) { fr(a), fr(b), fr(c); }
30     template<class T> inline char wr(T a, int b = 10, bool p = 1) {
31         return a < 0 ? pc('-'), wr(-a, b, 0) : (a == 0 ? (p ? pc('0') : p) :
32             (wr(a/b, b, 0), pc('0' + a % b)));
33     }
34     template<class T> inline void wt(T a) { wn(a); }
35     template<class T> inline void wt(T a, T b) { ws(a), wn(b); }
36     template<class T> inline void wt(T a, T b, T c) { ws(a), ws(b), wn(c); }
37     template<class T> inline void wt(T a, T b, T c, T d) { ws(a), ws(b), ws(c), wn(d); }
38     template<class T> inline T gcd(T a, T b) {
39         return b == 0 ? a : gcd(b, a % b); }
40     template<class T> inline T fpw(T b, T i, T _m, T r = 1) {
41         for(; i; i >>= 1, b = b * b % _m)
42             if(i & 1) r = r * b % _m;
43         return r; }
44 };
45 using namespace my_header;
46
47
48 int main() {
49 #ifdef lol
50     freopen("5982.in", "r", stdin);
51     freopen("5982.out", "w", stdout);
52 #endif
53
54     int T = fr();
55     while (T--) {
56         int n = fr();
57         int ans = 0;
58         for (int i = 1; i <= n; ++i)
59             ans += fr() * fr();
60         wt(ans);
61     }
62     return 0;
63 }