Problem:
Score : 300 points

Problem Statement

There are N stones arranged in a row. Every stone is painted white or black.
A string S represents the color of the stones. The i-th stone from the left is white if the i-th character of S is ., and the stone is black if the character is #.

Takahashi wants to change the colors of some stones to black or white so that there will be no white stone immediately to the right of a black stone.
Find the minimum number of stones that needs to be recolored.

Constraints

1 \leq N \leq 2\times 10^5

S is a string of length N consisting of . and #.

Input

Input is given from Standard Input in the following format:

N
S

Output

Print the minimum number of stones that needs to be recolored.

Sample Input 1

3
#.#

Sample Output 1

1

It is enough to change the color of the first stone to white.

Sample Input 2

5
#.##.

Sample Output 2

2

Sample Input 3

9
.........

Sample Output 3

0

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<bits/stdc++.h>
#define ll  long long
#define speed_up    ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define rep(i,a,b)  for(ll i=a;i<b;i++)
#define pb push_back
#define Max(x,y,z) max(x,max(y,z))
#define f first
#define s second
#define lbd lower_bound
#define sz(x)       (ll)x.size()
#define pi 3.1415926536
#define mod 1000000007
using namespace std;

void solve()
{
    ll n,m,k,x,y,res=0,l,a=0,b=0,c=0,d=0,cnt=0,sum=0,z;
    string s;
    cin>>n;
    cin>>s;
    bool yup=false;
    bool loda=false;
    for(ll i=n-1;i>=0;i--)
    {
        if(s[i]=='.')
            yup=true;
            if(s[i]=='#')
                loda=true;
            if(s[i]=='#' && yup==1)
            res++;
            if(s[i]=='.' && loda==1)
                cnt++;
    }
    cout<<min(cnt+1,res);
}
int main()
{
    ll t;
    //cin>>t;
    t=1;
    while(t--)
        solve();
}