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>
using namespace std;

template<typename T>
void remove(std::vector<T>& vector, unsigned int index) {
    vector.erase(vector.begin() + index);
}

template<class T>
T ma(vector<T> &v) {
    T maxi = 0;
    for (auto &i:v) maxi = max(maxi, i);
    return maxi;
}

#define rep(i, n, m) for (int i = n; i <= m; i++)
#define Rep(i, n, m) for (int i = m; i >= 1; i--)

typedef long long ll;
typedef unsigned long long ull;

long long ans = 0;

int main() {
    ull n;
    cin >> n;
    string s;
    cin >> s;
    ull black = 0, white = 0;
    rep(i, 0, s.size()-1)
        if (s[i] == '.') black++;
        else white++;
    cout << min(black, white) << endl;
}