#include<bits/stdc++.h>
using namespace std;
#define rep(i,j,k) for(int i=j;i<=k;++i)
#define repp(i,j,k) for(int i=j;i>=k;--i)
#define ll long long
#define N 200005
int n;
int r[N],s[N];
struct node {
    int pos,val;
    bool operator < (const node &a) const {
        return pos < a.pos;
    }
}e[2*N];
multiset<int>S;
void work() {
    cin>>n;
    rep(i,1,n) cin>>r[i]>>s[i] , e[2*i-1] = { max(i - r[i],1) , s[i] } , e[2*i] = { min(i + r[i] + 1,n+1) , -s[i] };
    sort( e + 1 , e + 2*n + 1 );
    S.clear();
    int ans = 0 , pos = -2*N , i = 1 , res = 0;
    for(;i <= 2*n;) {
        pos = e[i].pos;
        if( pos == n+1 ) break; 
        while( e[i].pos == pos ) {
            if( e[i].val > 0 ) S.insert( e[i].val );
            else S.erase( S.find( -e[i].val ) );
            ++i;
        }
        //printf("#%d %d %d\n",i,pos,(int)(S.size()));
        if( (int)(S.size()) >= 3 ) {
            auto it = S.end(); res = 0;
            rep(ttt,1,3) it-- , res += (*it);
            ans = max( ans , res );
        }
    }
    cout << ans << endl;
}
int main() {
    ios::sync_with_stdio(false), cin.tie(0);
    int T; cin >> T;
    while(T--) {
        work();
    }
    return 0;
}