Solving a problem during a programming contest is always a moment of happiness. During the CUET CSE fest programming contest, team solved status is denoted by a binary string of size where for all , means team has already solved this problem and means they haven’t solved this yet. Recall that a binary string is a non-empty sequence of characters where each character is either 0 or 1.
After a few hours of the contest, judge pc suddenly started acting weirdly. When a team solves a problem, the next problem automatically gets accepted. In other words, if solves problem that is becomes then also becomes if .
Team found this fault and wants to make the best use of it. Your task is to find the minimum number of submissions team needs to make to solve all the problems. Here you can assume that if team makes a submission then it gets accepted.
The first line contains the value of — the length of the binary string.
The second line contains a binary string and for all , is either or .
Print a single integer — minimum number of submissions team needs to make to solve all the problems.