int main(){
int test,n,number,i,j,max=0,maxNumber=0;
scanf("%d", &test);
for (i = 0; i < test; i++){
scanf("%d", &n);
for (j = 0; j < n; j++){
scanf("%d", &number);
if (getFirstDigit(number) > max){
max = getFirstDigit(number);
maxNumber = number;
}
}
printf("%d\n" , maxNumber);
maxNumber = 0;
max = 0;
}
return 0;
}
int countDigitOne(int n) {
int result = 0;
int firstDigit = getFirstDigit(n);
int numDigits = getNumDigits(n);
if (numDigits == 1) {
if (firstDigit >= 1)
result = 1;
}
else if (numDigits > 1) {
int remainder = n - firstDigit*pow(10, numDigits-1);
for (int k = 1; k < numDigits; k++)
result += numOneInNDigitNumbers(k);
if (firstDigit > 1) {
int sum = 0;
for (int k = 1; k < numDigits; k++)
sum += numOneInNDigitNumbers(k);
result += pow(10, numDigits-1)+(firstDigit-1)*sum;
}
else
result += remainder+1;
result += countDigitOne(remainder);
}
return result;
}