What is the worst$-$case complexity of the sumUp function?

class OddSum $\{$

private:

int$*$ counts;

int $nC$;

public:

NameCounter $($int nCounts, int nNames$)$;

int sumUp$()$ const;

$\}$;

$...$

int NameCounter::sumUp $()$

$\{$

int sum $=0$;

for $($int $j=i-1$;$ji+1$;$++j+=$counts$[j]i=1$;$i$