Busiest Intersection

You are given traffic data from several intersections. For each test case, you need to determine the intersection with the highest total vehicle count. In the event of a tie, choose the intersection with the lexicographically smallest identifier.

Formally, for each test case with N intersections where each intersection is represented by a pair \( (s, c) \) (with \( s \) being the intersection identifier and \( c \) the vehicle count), find the intersection \( s^* \) such that

[ s^* = \min_{s \in S} { s : c = \max_{(s,c) \in S} c } ]

where \( S \) is the set of intersections in the test case. Output the answer for each test case on a new line.

inputFormat

The first line of input contains an integer \( T \) representing the number of test cases. For each test case:

• The first line contains an integer \( N \) representing the number of intersections.
• The next \( N \) lines each contain an intersection identifier (a string without spaces) and an integer representing the vehicle count, separated by a space.

Input is read from standard input.

outputFormat

For each test case, output a single line containing the identifier of the busiest intersection. Output is written to standard output.

## sample

2
3
A1 1500
B2 2000
C3 1500
4
X1 1000
Y2 3000
Z3 3000
W4 2500

B2
Y2

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